USE flag index

What are USE flags?
For more information on the idea behind USE flags and how to use them, please see our documentation.

Global USE flags

Flag Description
X Add support for X11
Xaw3d Add support for the 3d athena widget set
a52 Enable support for decoding ATSC A/52 streams used in DVD
aac Enable support for MPEG-4 AAC Audio
aalib Add support for media-libs/aalib (ASCII-Graphics Library)
accessibility Add support for accessibility (eg 'at-spi' library)
acl Add support for Access Control Lists
acpi Add support for Advanced Configuration and Power Interface
adns Add support for asynchronous DNS resolution
afs Add OpenAFS support (distributed file system)
alsa Add support for media-libs/alsa-lib (Advanced Linux Sound Architecture)
ao Use libao audio output library for sound playback
apache2 Add Apache2 support
aqua Include support for the Mac OS X Aqua (Carbon/Cocoa) GUI
atm Enable Asynchronous Transfer Mode protocol support
apparmor Enable support for the AppArmor application security system
appindicator Build in support for notifications using the libindicate or libappindicator plugin
audiofile Add support for libaudiofile where applicable
audit Enable support for Linux audit subsystem using sys-process/audit
avif Add AV1 Image Format (AVIF) support
bash-completion Enable bash-completion support
berkdb Add support for sys-libs/db (Berkeley DB for MySQL)
bidi Enable bidirectional language support
big-endian Big-endian toolchain support
bindist Flag to enable or disable options for prebuilt (GRP) packages (eg. due to licensing issues)
blas Add support for the virtual/blas numerical library
bluetooth Enable Bluetooth Support
branding Enable Gentoo specific branding
brotli Enable Brotli compression support
build !!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used for creating build images and the first half of bootstrapping [make stage1]
bzip2 Enable bzip2 compression support
cairo Enable support for the cairo graphics library
calendar Add support for calendars (not using mcal!)
caps Use Linux capabilities library to control privilege
cdb Add support for the CDB database engine from the author of qmail
cdda Add Compact Disk Digital Audio (Standard Audio CD) support
cddb Access cddb servers to retrieve and submit information about compact disks
cdinstall Copy files from the CD rather than asking the user to copy them, mostly used with games
cdr Add support for CD writer hardware
cgi Add CGI script support
cjk Add support for Multi-byte character languages (Chinese, Japanese, Korean)
clamav Add support for Clam AntiVirus software (usually with a plugin)
colord Support color management using x11-misc/colord
connman Add support for net-misc/connman
coreaudio Build the CoreAudio driver on Mac OS X systems
cracklib Support for cracklib strong password checking
crypt Add support for encryption -- using mcrypt or gpg where applicable
css Enable reading of encrypted DVDs
cups Add support for CUPS (Common Unix Printing System)
curl Add support for client-side URL transfer library
custom-cflags Build with user-specified CFLAGS (unsupported)
cvs Enable CVS (Concurrent Versions System) integration
cxx Build support for C++ (bindings, extra libraries, code generation, ...)
dbi Enable dev-db/libdbi (database-independent abstraction layer) support
dbm Add support for generic DBM databases
dbus Enable dbus support for anything that needs it (gpsd, gnomemeeting, etc)
debug Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
dedicated Add support for dedicated game servers (some packages do not provide clients and servers at the same time)
dga Add DGA (Direct Graphic Access) support for X
dist-kernel Enable subslot rebuilds on Distribution Kernel upgrades
djvu Support DjVu, a PDF-like document format esp. suited for scanned documents
doc Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
dri Enable direct rendering: used for accelerated 3D and some 2D, like DMA
dts Enable DTS Coherent Acoustics decoder support
dv Enable support for a codec used by many camcorders
dvb Add support for DVB (Digital Video Broadcasting)
dvd Add support for DVDs
dvdr Add support for DVD writer hardware (e.g. in xcdroast)
eds Enable support for Evolution-Data-Server (EDS)
elogind Enable session tracking via sys-auth/elogind
emacs Add support for GNU Emacs
emboss Add support for the European Molecular Biology Open Software Suite
encode Add support for encoding of audio or video files
examples Install examples, usually source code
exif Add support for reading EXIF headers from JPEG and TIFF images
expat Enable the use of dev-libs/expat for XML parsing
fam Enable FAM (File Alteration Monitor) support
fastcgi Add support for the FastCGI interface
fbcon Add framebuffer support for the console, via the kernel
ffmpeg Enable ffmpeg/libav-based audio/video codec support
fftw Use FFTW library for computing Fourier transforms
filecaps Use Linux file capabilities to control privilege rather than set*id (this is orthogonal to USE=caps which uses capabilities at runtime e.g. libcap)
firebird Add support for the Firebird relational database
flac Add support for FLAC: Free Lossless Audio Codec
fltk Add support for the Fast Light Toolkit gui interface
fontconfig Support for configuring and customizing font access via media-libs/fontconfig
fortran Add support for fortran
freetds Add support for the TDS protocol to connect to MSSQL/Sybase databases
freewnn Add support for FreeWnn kana to kanji conversion engine
ftp Add FTP (File Transfer Protocol) support
gd Add support for media-libs/gd (to generate graphics on the fly)
gdbm Add support for sys-libs/gdbm (GNU database libraries)
geoip Add geoip support for country and city lookup based on IPs
geolocation Enable physical position determination
ggi Add support for media-libs/libggi (non-X video api/drivers)
gif Add GIF image support
gimp Build a plugin for the GIMP
git Enable git (version control system) support
gles2-only Use GLES 2.0 or later instead of full OpenGL
glut Build an OpenGL plugin using the GLUT library
gmp Add support for dev-libs/gmp (GNU MP library)
gnome Add GNOME support
gnome-keyring Enable support for storing passwords via gnome-keyring
gnuplot Enable support for gnuplot (data and function plotting)
gnutls Prefer net-libs/gnutls as SSL/TLS provider (ineffective with USE=-ssl)
gphoto2 Add digital camera support
gpm Add support for sys-libs/gpm (Console-based mouse driver)
gps Add support for Global Positioning System
graphicsmagick Build and link against GraphicsMagick instead of ImageMagick (requires USE=imagemagick if optional)
graphviz Add support for the Graphviz library
gsl Use the GNU scientific library for calculations
gsm Add support for the gsm lossy speech compression codec
gstreamer Add support for media-libs/gstreamer (Streaming media)
gtk Add support for x11-libs/gtk+ (The GIMP Toolkit)
gtk-doc Build and install gtk-doc based developer documentation for dev-util/devhelp, IDE and offline use
gui Enable support for a graphical user interface
guile Add support for the guile Scheme interpreter
gzip Compress files with Lempel-Ziv coding (LZ77)
handbook Enable handbooks generation for packages by KDE
hardened Activate default security enhancements for toolchain (gcc, glibc, binutils)
hddtemp Enable monitoring of hdd temperature (app-admin/hddtemp)
hdf5 Add support for the Hierarchical Data Format v5
headers-only Install only C headers instead of whole package. Mainly used by sys-devel/crossdev for toolchain bootstrap.
heif Enable support for ISO/IEC 23008-12:2017 HEIF/HEIC image format
hscolour Include coloured haskell sources to generated documentation (dev-haskell/hscolour)
ibm Add support for IBM ppc64 specific systems
iconv Enable support for the iconv character set conversion library
icu Enable ICU (Internationalization Components for Unicode) support, using dev-libs/icu
idn Enable support for Internationalized Domain Names
ieee1394 Enable FireWire/iLink IEEE1394 support (dv, camera, ...)
imagemagick Enable optional support for the ImageMagick or GraphicsMagick image converter
imap Add support for IMAP (Internet Mail Application Protocol)
imlib Add support for imlib, an image loading and rendering library
infiniband Enable Infiniband RDMA transport support
inotify Enable inotify filesystem monitoring support
introspection Add support for GObject based introspection
iodbc Add support for iODBC library
ios Enable support for Apple's iDevice with iOS operating system (iPad, iPhone, iPod, etc)
ipod Enable support for iPod device access
ipv6 Add support for IP version 6
jack Add support for the JACK Audio Connection Kit
java Add support for Java
javascript Enable javascript support
jbig Enable jbig-kit support for tiff, Hylafax, ImageMagick, etc
jemalloc Use dev-libs/jemalloc for memory management
jit Enable just-in-time compilation for improved performance. May prevent use of some PaX memory protection features in Gentoo Hardened.
joystick Add support for joysticks in all packages
jpeg Add JPEG image support
jpeg2k Support for JPEG 2000, a wavelet-based image compression format
jpegxl Add JPEG XL image support
kde Add support for software made by KDE, a free software community
kerberos Add kerberos support
keyring Enable support for freedesktop.org Secret Service API password store
ladspa Enable the ability to support ladspa plugins
lame Prefer using LAME libraries for MP3 encoding support
lapack Add support for the virtual/lapack numerical library
lash Add LASH Audio Session Handler support
latex Add support for LaTeX (typesetting package)
lcms Add lcms support (color management engine)
ldap Add LDAP support (Lightweight Directory Access Protocol)
libass SRT/SSA/ASS (SubRip / SubStation Alpha) subtitle support
libcaca Add support for colored ASCII-art graphics
libedit Use the libedit library (replacement for readline)
libffi Enable support for Foreign Function Interface library
libnotify Enable desktop notification support
libsamplerate Build with support for converting sample rates using libsamplerate
libwww Add libwww support (General purpose WEB API)
lirc Add support for lirc (Linux's Infra-Red Remote Control)
livecd !!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used during livecd building
llvm-libunwind Use sys-libs/llvm-libunwind instead of sys-libs/libunwind
lm-sensors Add linux lm-sensors (hardware sensors) support
lua Enable Lua scripting support
lz4 Enable support for lz4 compression (as implemented in app-arch/lz4)
lzip Enable support for lzip compression
lzma Support for LZMA compression algorithm
lzo Enable support for lzo compression
m17n-lib Enable m17n-lib support
mad Add support for mad (high-quality mp3 decoder library and cli frontend)
magic Add support for file type detection via magic bytes (usually via libmagic from sys-apps/file)
maildir Add support for maildir (~/.maildir) style mail spools
man Build and install man pages
matroska Add support for the matroska container format (extensions .mkv, .mka and .mks)
mbox Add support for mbox (/var/spool/mail) style mail spools
memcached Add support for memcached
mhash Add support for the mhash library
mikmod Add libmikmod support to allow playing of SoundTracker-style music files
milter Add sendmail mail filter (milter) support
minimal Install a very minimal build (disables, for example, plugins, fonts, most drivers, non-critical features)
mmap Add mmap (memory map) support
mms Support for Microsoft Media Server (MMS) streams
mng Add support for libmng (MNG images)
modplug Add libmodplug support for playing SoundTracker-style music files
modules Build the kernel modules
modules-sign Cryptographically sign installed kernel modules (requires CONFIG_MODULE_SIG=y in the kernel)
mono Build Mono bindings to support dotnet type stuff
motif Add support for the Motif toolkit
mp3 Add support for reading mp3 files
mp4 Support for MP4 container format
mpeg Add libmpeg3 support to various packages
mpi Add MPI (Message Passing Interface) layer to the apps that support it
mplayer Enable mplayer support for playback or encoding
mssql Add support for Microsoft SQL Server database
mtp Enable support for Media Transfer Protocol
multilib On 64bit systems, if you want to be able to compile 32bit and 64bit binaries
musepack Enable support for the musepack audio codec
musicbrainz Lookup audio metadata using MusicBrainz community service (musicbrainz.org)
mysql Add mySQL Database support
mysqli Add support for the improved mySQL libraries
nas Add support for network audio sound
native-extensions Build native (e.g. C, Rust) extensions in addition to pure (e.g. Python) code (usually speedups)
ncurses Add ncurses support (console display library)
neXt Enable neXt toolkit
netcdf Enable NetCDF data format support
networkmanager Enable net-misc/networkmanager support
nis Support for NIS/YP services
nls Add Native Language Support (using gettext - GNU locale utilities)
nntp Add support for newsgroups (Network News Transfer Protocol)
nocd Install all files required to run the application without a CD mounted
nsplugin Build plugin for browsers supporting the Netscape plugin architecture (that is almost any modern browser)
nvenc Add support for NVIDIA Encoder/Decoder (NVENC/NVDEC) API for hardware accelerated encoding and decoding on NVIDIA cards (requires x11-drivers/nvidia-drivers)
ocaml Add support/bindings for the Ocaml language
ocamlopt Enable ocamlopt support (ocaml native code compiler) -- Produces faster programs (Warning: you have to disable/enable it at a global scale)
oci8 Add Oracle 8 Database Support
oci8-instant-client Use dev-db/oracle-instantclient-basic as Oracle provider instead of requiring a full Oracle server install
odbc Add ODBC Support (Open DataBase Connectivity)
offensive Enable potentially offensive items in packages
ofx Enable support for importing (and exporting) OFX (Open Financial eXchange) data files
ogg Add support for the Ogg container format (commonly used by Vorbis, Theora and flac)
openal Add support for the Open Audio Library
openexr Support for the OpenEXR graphics file format
opengl Add support for OpenGL (3D graphics)
openmp Build support for the OpenMP (support parallel computing), requires >=sys-devel/gcc-4.2 built with USE="openmp"
opentype-compat Convert BDF and PCF bitmap fonts to OTB wrapper format
opus Enable Opus audio codec support
oracle Enable Oracle Database support
orc Use dev-lang/orc for just-in-time optimization of array operations
osc Enable support for Open Sound Control
oss Add support for OSS (Open Sound System)
pam Add support for PAM (Pluggable Authentication Modules) - DANGEROUS to arbitrarily flip
pch Enable precompiled header support for faster compilation at the expense of disk space and memory (>=sys-devel/gcc-3.4 only)
pcmcia Add support for PCMCIA slots/devices found on laptop computers
pcre Add support for Perl Compatible Regular Expressions
pda Add support for portable devices
pdf Add general support for PDF (Portable Document Format), this replaces the pdflib and cpdflib flags
perl Add optional support/bindings for the Perl language
php Include support for the PHP language
pie Build programs as Position Independent Executables (a security hardening technique)
plasma Build optional KDE plasma addons
plotutils Add support for plotutils (library for 2-D vector graphics)
png Add support for libpng (PNG images)
policykit Enable PolicyKit (polkit) authentication support
portaudio Add support for the crossplatform portaudio audio API
posix Add support for POSIX-compatible functions
postgres Add support for the postgresql database
postscript Enable support for the PostScript language (often with ghostscript-gpl or libspectre)
ppds Add support for automatically generated ppd (printing driver) files
prefix Defines if a Gentoo Prefix offset installation is used
profile Add support for software performance analysis (will likely vary from ebuild to ebuild)
pulseaudio Add sound server support via media-libs/libpulse (may be PulseAudio or PipeWire)
python Add optional support/bindings for the Python language
qdbm Add support for the qdbm (Quick Database Manager) library
qmail-spp Add support for qmail SMTP plugins
qt5 Add support for the Qt 5 application and UI framework
qt6 Add support for the Qt 6 application and UI framework
quicktime Add support for OpenQuickTime
radius Add support for RADIUS authentication
raw Add support for raw image formats
rdp Enables RDP/Remote Desktop support
readline Enable support for libreadline, a GNU line-editing library that almost everyone wants
recode Enable support for the GNU recode library
rss Enable support for RSS feeds
ruby Add support/bindings for the Ruby language
samba Add support for SAMBA (Windows File and Printer sharing)
sasl Add support for the Simple Authentication and Security Layer
savedconfig Use this to restore your config from /etc/portage/savedconfig ${CATEGORY}/${PN}. Make sure your USE flags allow for appropriate dependencies
scanner Add support for scanner hardware (e.g. build the sane frontend in kdegraphics)
screencast Enable support for remote desktop and screen cast using PipeWire
sctp Support for Stream Control Transmission Protocol
sdl Add support for Simple Direct Layer (media library)
seccomp Enable seccomp (secure computing mode) to perform system call filtering at runtime to increase security of programs
secureboot Automatically sign efi executables using user specified key
selinux !!internal use only!! Security Enhanced Linux support, this must be set by the selinux profile or breakage will occur
semantic-desktop Cross-KDE support for semantic search and information retrieval
session Add persistent session support
skey Enable S/Key (Single use password) authentication support
slang Add support for the slang text display library (it's like ncurses, but different)
smartcard Enable smartcard support
smp Enable support for multiprocessors or multicore systems
snappy Enable support for Snappy compression (as implemented in app-arch/snappy)
sndfile Add support for libsndfile
snmp Add support for the Simple Network Management Protocol if available
soap Add support for SOAP (Simple Object Access Protocol)
sockets Add support for tcp/ip sockets
socks5 Add support for the socks5 proxy
sound Enable sound support
source Zip the sources and install them
sox Add support for Sound eXchange (SoX)
speex Add support for the speex audio codec (used for speech)
spell Add dictionary support
split-usr Enable behavior to support maintaining /bin, /lib*, /sbin and /usr/sbin separately from /usr/bin and /usr/lib*
sqlite Add support for sqlite - embedded sql database
ssl Add support for SSL/TLS connections (Secure Socket Layer / Transport Layer Security)
startup-notification Enable application startup event feedback mechanism
static !!do not set this during bootstrap!! Causes binaries to be statically linked instead of dynamically
static-libs Build static versions of dynamic libraries as well
strip Allow symbol stripping to be performed by the ebuild for special files
subversion Enable subversion (version control system) support
suid Enable setuid root program(s)
svg Add support for SVG (Scalable Vector Graphics)
svga Add support for SVGAlib (graphics library)
symlink Force kernel ebuilds to automatically update the /usr/src/linux symlink
syslog Enable support for syslog
systemd Enable use of systemd-specific libraries and features like socket activation or session tracking
szip Use the szip compression library
taglib Enable tagging support with taglib
tcl Add support the Tcl language
tcmalloc Use the dev-util/google-perftools libraries to replace the malloc() implementation with a possibly faster one
tcpd Add support for TCP wrappers
telemetry Send anonymized usage information to upstream so they can better understand our users
test Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)
test-rust Enable important test dependencies that require Rust toolchain
theora Add support for the Theora Video Compression Codec
threads Add threads support for various packages. Usually pthreads
tidy Add support for HTML Tidy
tiff Add support for the TIFF image format
timidity Build with Timidity++ (MIDI sequencer) support
tk Add support for Tk GUI toolkit
truetype Add support for FreeType and/or FreeType2 fonts
udev Enable virtual/udev integration (device discovery, power and storage device support, etc)
udisks Enable storage management support (automounting, volume monitoring, etc)
uefi Enable support for the Unified Extensible Firmware Interface
unicode Add support for Unicode
unwind Add support for call stack unwinding and function name resolution
upnp Enable UPnP port mapping support
upnp-av Enable UPnP audio/video streaming support
upower Enable power management support
usb Add USB support to applications that have optional USB support (e.g. cups)
v4l Enable support for video4linux (using linux-headers or userspace libv4l libraries)
vaapi Enable Video Acceleration API for hardware decoding
vala Enable bindings for dev-lang/vala
valgrind Enable annotations for accuracy. May slow down runtime slightly. Safe to use even if not currently using dev-util/valgrind
vanilla Do not add extra patches which change default behaviour; DO NOT USE THIS ON A GLOBAL SCALE as the severity of the meaning changes drastically
vcd Video CD support
vdpau Enable the Video Decode and Presentation API for Unix acceleration interface
verify-sig Verify upstream signatures on distfiles
vhosts Add support for installing web-based applications into a virtual-hosting environment
videos Install optional video files (used in some games)
vim-syntax Pulls in related vim syntax scripts
vnc Enable VNC (remote desktop viewer) support
vorbis Add support for the OggVorbis audio codec
vulkan Add support for 3D graphics and computing via the Vulkan cross-platform API
wavpack Add support for wavpack audio compression tools
wayland Enable dev-libs/wayland backend
webkit Add support for the WebKit HTML rendering/layout engine
webp Add support for the WebP image format
wifi Enable wireless network functions
wmf Add support for the Windows Metafile vector image format
wxwidgets Add support for wxWidgets/wxGTK GUI toolkit
x264 Enable h264 encoding using x264
xattr Add support for extended attributes (filesystem-stored metadata)
xcb Support the X C-language Binding, a replacement for Xlib
xcomposite Enable support for the Xorg composite extension
xemacs Add support for XEmacs
xface Add xface support used to allow a small image of xface format to be included in an email via the header 'X-Face'
xft Build with support for XFT font renderer (x11-libs/libXft)
xine Add support for the XINE movie libraries
xinerama Add support for querying multi-monitor screen geometry through the Xinerama API
xinetd Add support for the xinetd super-server
xml Add support for XML files
xmlrpc Support for xml-rpc library
xmp Enable support for Extensible Metadata Platform (Adobe XMP)
xmpp Enable support for Extensible Messaging and Presence Protocol (XMPP) formerly known as Jabber
xosd Sends display using the X On Screen Display library
xpm Add support for XPM graphics format
xscreensaver Add support for XScreenSaver extension
xv Add in optional support for the Xvideo extension (an X API for video playback)
xvid Add support for xvid.org's open-source mpeg-4 codec
zeroconf Support for DNS Service Discovery (DNS-SD)
zip Enable support for ZIP archives
zlib Add support for zlib compression
zsh-completion Enable zsh completion support
zstd Enable support for ZSTD compression

Local USE flags

acct-user

git

gitea Set home directory for git hosting via www-apps/gitea.
gitolite Set home directory for git hosting via dev-vcs/gitolite or dev-vcs/gitolite-gentoo.

vdr

graphlcd Prepare group membership for media-plugins/vdr-graphlcd.
legacy-homedir Keep old home directory /var/vdr of an existing installation. When this useflag is cleared, the home directory is switched to FHS conformant /var/lib/vdr
remote Prepare group membership for media-plugins/vdr-remote.
serial Prepare group membership for media-plugins/vdr-serial.

app-accessibility

at-spi2-core

dbus-broker Use DBus broker implementation instead of default DBus daemon

brltty

api build brltty's application program interface
beeper support the console tone generator
fm support for the sound card synthesizer
louis Use braille translator dev-libs/liblouis
midi support the musical instrument digital interface
pcm support for sound card digital audio
speech speech support

emacspeak

espeak Adds support for the espeak tts engine

espeak-ng

async Enables asynchronous commands
klatt Enables Klatt formant synthesis and implementation
l10n_ru Builds extended Russian Dictionary file
l10n_zh Builds extended Chinese (Mandarin and Cantonese) Dictionary files
man Builds and installs manpage with app-text/ronn-ng
mbrola Adds support for mbrola voices

flite

voices Install synthetic voices

freetts

jsapi build Java Speech API (JSAPI)
mbrola Adds support for mbrola voices

orca

braille Enable braille support

speech-dispatcher

espeak Adds support for espeak-ng speech engine
flite Adds support for flite speech engine

app-admin

clsync

apidoc Provide doxygen generated API docs.
cgroups Use cgroups to limit /dev access.
clsync Build clsync binary. Most likely you want it. However it is possible to build only libclsync without clsync itself.
cluster Enable clustering support (allows master-master clsync on multiple hosts). Not fully implemented yet.
control-socket Enable AF_UNIX control socket support.
extra-debug Enable extra debugging. This will hurt performance badly. Be ready for tons of output.
extra-hardened Enable extra security checks. This will hurt performance.
gio Enable GIO for FS monitoring (glib based alternative to inotify interface, not recommended; if both are compiled, may be selected at runtime).
highload-locks Allows to use spinlocks for short delays instead of mutexes, but only on SMP systems.
lto Build with link time optimization (LTO).
namespaces Enable namespaces isolation.
socket-library Build the control and monitoring socket library: libclsync.

conky

apcupsd Enable support for sys-power/apcupsd
bundled-toluapp Enable support for bundled toluapp. This only makes sense in combination with the lua-* flags
cmus Enable monitoring of music played by media-sound/cmus
extras Enable syntax highlighting for app-editors/nanoand app-editors/vim
ical Enable support for events from iCalendar (RFC 5545) files using dev-libs/libical
intel-backlight Enable support for Intel backlight
iostats Enable support for per-task I/O statistics
irc Enable support for displaying everything from an irc channel using net-libs/libircclient
lua-cairo Enable if you want Lua Cairo bindings
lua-imlib Enable if you want Lua Imlib2 bindings
lua-rsvg Enable if you want Lua RSVG bindings
math Enable support for glibc's libm math library
moc Enable monitoring of music played by media-sound/moc
mpd Enable monitoring of music controlled by media-sound/mpd
nvidia Enable reading of nvidia card temperature sensors via x11-drivers/nvidia-drivers
portmon Enable support for tcp (ip4) port monitoring
thinkpad Enable support for IBM/Lenovo notebooks
webserver Enable support to act as a webserver serving conkys output using net-libs/libmicrohttpd
xmms2 Enable monitoring of music played by media-sound/xmms2

conserver

freeipmi Compile in FreeIPMI support via sys-libs/freeipmi

diradm

automount Support for automount data in LDAP
irixpasswd Support for storing separate IRIX passwords

doas

persist Adds support for "persist" feature (experimental)

gkrellm

X Build both the X11 gui (gkrellm) and the server (gkrellmd). Disabling this flag builds the server only
gnutls Enable SSL support for mail checking with net-libs/gnutls (overrides 'ssl' USE flag)
lm-sensors Enable monitoring sensors via sys-apps/lm-sensors
ntlm Enable NTLM authentication for mail checking with net-libs/libntlm
ssl Enable SSL support for mail checking with dev-libs/openssl

gtkdiskfree

gtk2 Support GTK+ 2.x instead of GTK+ 3.x

hddtemp

network-cron Monthly cronjob to update hddtemp.db.

keepass

aot Generate native code at build time, rather than runtime.

keepassxc

autotype Add support to autotype the passwords into other applications
browser Enables browser plugin support
keeshare Enable KeeShare sharing integration
network Enable network support
yubikey Enable database unlocking via hardware keys supporting YubiKey-style HMAC-SHA1 protocol

lnav

pcap Enable support for pcap files.

logcheck

cron Adds file to enable hourly cron job to run logcheck"

logrotate

acl Installs acl support
cron Installs cron file
selinux Installs Security Enhanced Linux support

logstash-bin

x-pack Enable additional features (may need a license)

openrc-settingsd

systemd Use the versions of dbus and polkit files provided by sys-apps/systemd

pass

X Use x11-misc/xclip to copy passwords to the clipboard.
dmenu Add support for x11-misc/dmenu with the 'passmenu' program.
git Use dev-vcs/git for password revisions.
importers Allow importing passwords from other password managers using various contributed scripts.

pass-otp

qrcode Add support for qrcodes using media-gfx/qrencode

passwordsafe

qr Enable QR code password display
xml Enable XML import support
yubikey Enable support for Yubikey

perl-cleaner

pkgcore Use sys-apps/pkgcore instead of sys-apps/portage and app-portage/portage-utils.

puppet

augeas Enable augeas support
diff Enable diff support
hiera Enable hiera support
rrdtool Enable rrdtool support
shadow Enable shadow support

puppet-agent

puppetdb Adds puppetdb support

puppetserver

puppetdb Adds support for connecting to puppetdb

pwgen

livecd Install init script for root password scrambling on boot

rsyslog

clickhouse Build the ClickHouse output module (requires net-misc/curl)
curl Enable http_request() function in RainerScript (requires net-misc/curl)
dbi Build the general database output module (requires dev-db/libdbi)
elasticsearch Build the Elasticsearch output module (requires net-misc/curl)
gcrypt Add support for encrypted log files using dev-libs/libgcrypt
gnutls Build the GnuTLS network stream driver (requires net-libs/gnutls)
imhttp Build the http input module (requires www-servers/civetweb)
impcap Build the pcap input module (requires net-libs/libpcap)
kafka Build the Apache Kafka input/output module (requires dev-libs/librdkafka)
kerberos Build the GSSAPI input and output module (requires virtual/krb5)
kubernetes Build the kubernetes modify plugin (requires net-misc/curl)
mdblookup Build the MaxMind DB lookup message modify plugin using dev-libs/libmaxminddb
mongodb Build the MongoDB output module (requires dev-libs/mongo-c-driver)
mysql Build the MySQL database output module (requires virtual/mysql)
normalize Build the normalize modify module (requires dev-libs/libee and dev-libs/liblognorm)
omhttp Build the http output module (requires net-misc/curl)
omhttpfs Build the httpfs output module (requires net-misc/curl)
omudpspoof Build the udpspoof output module (requires net-libs/libnet)
openssl Build the OpenSSL network stream driver (requires dev-libs/openssl)
postgres Build the PostgreSQL database output module (requires dev-db/postgresql)
rabbitmq Build the RabbitMQ output module (requires net-libs/rabbitmq-c)
redis Build the Redis output module using (requires dev-libs/hiredis)
relp Build the Reliable Event Logging Protocol (RELP) output module (requires dev-libs/librelp)
rfc3195 Build the rfc3195 input module (requires dev-libs/liblogging)
rfc5424hmac Build the rfc5424hmac modify module (requires dev-libs/openssl)
snmp Build the snmp modify and output module (requires net-analyzer/net-snmp)
ssl Add support for encrypted client/server communication (requires net-libs/gnutls)
systemd Build the journal input and output module (requires sys-apps/systemd)
usertools Installs the user tools (rsgtutil, rscryutil...) corresponding to the set USE flags
uuid Include UUIDs in messages (requires sys-apps/util-linux)
xxhash Enable xxHash support in fmhash module (requires dev-libs/xxhash)
zeromq Build the ZeroMQ input and output modules (requires net-libs/czmq)

sagan

libdnet Add support for dev-libs/libdnet
pcap Add support for network packet capture via net-libs/libpcap
redis Add support for the Redis database via dev-libs/hiredis
smtp Build witch SMTP (E-Mail) support

salt

cheetah Enable support for dev-python/cheetah3
cherrypy Enable support for using cherrypy.
genshi Enable support for dev-python/genshi
gnupg Enable support for gnupg via python-gnupg.
libcloud Enable salt-cloud support via libcloud.
libvirt Support managing virtual machines with app-emulation/libvirt.
mako Add support for using the mako template engine for parsing salt states.
mongodb Support returning data to a mongodb server.
neutron Support the OpenStack neutron network service.
nova Enable support for the OpenStack Nova API
openssl Add support for using TLS via OpenSSL.
portage Add support for package state enforcement using sys-apps/portage
raet Add support for the new RAET transport.
redis Support returning data to a redis database.
zeromq Add support for the zeromq transport.

sudo

gcrypt Use message digest functions from dev-libs/libgcrypt instead of sudo's
offensive Let sudo print insults when the user types the wrong password
secure-path Replace PATH variable with compile time secure paths
sendmail Allow sudo to send emails with sendmail
sssd Add System Security Services Daemon support

sysklogd

logger Build the logger program
logrotate use app-admin/logrotate for rotating logs rather than custom cron scripts

syslog-ng

amqp Enable support for AMQP destinations
geoip2 Add support for geo lookup based on IPs via dev-libs/libmaxminddb
http Enable support for HTTP destinations
json Enable support for JSON template formatting via dev-libs/json-c
kafka Enable support for Kafka destinations
mongodb Enable support for mongodb destinations
pacct Enable support for reading Process Accounting files (EXPERIMENTAL, Linux only)
redis Enable support for Redis destinations
smtp Enable support for SMTP destinations
spoof-source Enable support for spoofed source addresses

sysstat

dcron Adjust cronjobs to work properly under sys-process/dcron
lto Build using Link Time Optimizations (LTO)

testdisk

ewf Include ewf library
ntfs Include the ability to read NTFS filesystems
reiserfs Include reiserfs reading ability

tripwire

ssl Adds support for Secure Socket Layer connections
static Builds the package statically
tools Installs app-admin/mktwpol, providing scripts for the installation/setup of tripwire, including generating the tripwire policy file and maintenance of the tripwire database

ulogd

json Build JSON output plugin to save packets in JSON file format
nfacct Build NFACCT input plugin to support traffic accounting via nfnetlink_acct
nfct Build NFCT input plugin to support stateful flow-based logging via nfnetlink_conntrack
nflog Build NFLOG input plugin to support stateless packet-based logging via nfnetlink_log
pcap Build PCAP output plugin to save packets in libpcap file format
ulog Build ULOG input plugin to support deprecated packet-based logging via ULOG target

vault

webui Enable the Web UI

webalizer

xtended Include the 404 extension

webapp-config

portage Propagate python_targets dependencies to sys-apps/portage

app-alternatives

awk

busybox Symlink to sys-apps/busybox
gawk Symlink to sys-apps/gawk
mawk Symlink to sys-apps/mawk (warning: mawk is not fully POSIX-compliant)
nawk Symlink to sys-apps/nawk

bc

gh Symlink to bc-gh from sci-calculators/bc-gh
gnu Symlink to GNU bc (sys-devel/bc)

bzip2

lbzip2 Symlink to app-arch/lbzip2.
pbzip2 Symlink to app-arch/pbzip2.
reference Symlink to app-arch/bzip2.

cpio

gnu Symlink to GNU cpio (app-arch/cpio)
libarchive Symlink to bsdcpio from app-arch/libarchive

gzip

pigz Symlink to app-arch/pigz.
reference Symlink to app-arch/gzip.

lex

flex Symlink to sys-devel/flex.
reflex Symlink to sys-devel/reflex.

ninja

reference Symlink to dev-util/ninja.
samurai Symlink to dev-util/samurai.

sh

bash Symlink to app-shells/bash
busybox Symlink to sys-apps/busybox
dash Symlink to app-shells/dash
ksh Symlink to app-shells/ksh
lksh Symlink to lksh from app-shells/mksh
mksh Symlink to mksh from app-shells/mksh

tar

gnu Symlink to GNU tar (app-arch/tar)
libarchive Symlink to bsdtar from app-arch/libarchive

yacc

bison Symlink to sys-devel/bison.
byacc Symlink to dev-util/byacc.
reference Symlink to dev-util/yacc.

app-antivirus

clamav

clamapp Build applications (clamscan, clamd, clamdscan, clamonacc (also has its own USE flag), sigtool, clambc, clamav-milter (also requires milter USE flag), clamdtop, clamsubmit, clamconf).
clamdtop A Top like tool which shows what clamd is currently scanning amongst other things
clamonacc Build the clamonacc on-access scanner
clamsubmit A tool to submit false positives / negatives
experimental Enable experimental features
libclamav-only Bypass building of libfreshclam and the ClamAV CLI applications.
metadata-analysis-api Enables collection of file property metadata using ClamAV API for analysis by ClamAV bytecode programs.
rar RAR support
system-mspack Use dev-libs/libmspack instead of the version bundled with ClamAV
xml DMG and XAR support

clamtk

kde Install the Dolphin plugin.
nautilus Install the Nautilus plugin.
nemo Install the Nemo plugin.
thunar Install the Thunar plugin.

app-arch

cabextract

extras Install experimental extra tools: wince_info and wince_rename for examining and processing Windows CE installation cabinet header files; cabinfo for examining the structure of a cab file.

createrepo_c

legacy Build with support for legacy weakdeps and hashes (not recommended!)

dpkg

libmd Use app-crypt/libmd library for message digest functions
update-alternatives Install update-alternatives

dump

ermt encrypted rmt support
uuid Enable UUID support

engrampa

caja Enable engrampa to integrate with mate-base/caja by providing entries in its context menu

file-roller

nautilus Build contextual menu extension for gnome-base/nautilus.

gzip

pic disable optimized assembly code that is not PIC friendly

innoextract

debug Enable debug logging and the --debug command-line option
lzma Enable support for extracting lzma-compressed installers using app-arch/xz-utils

libarchive

blake2 Enable Blake2 hash support via app-crypt/libb2.
bzip2 Allow accessing bzip2-compressed archives through libbz2 (which comes with app-arch/bzip2). This only affects libarchive's native support: bsdtar will keep using bunzip2 as a filter if that's not built-in.
e2fsprogs Use file flags from sys-fs/e2fsprogs headers instead of virtual/os-headers headers
nettle Use dev-libs/nettle as crypto backend

p7zip

natspec Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.
rar Enable support for non-free rar decoder

rar

all-sfx Install all SFX (Self-Extracting) files rather than just the native format (allows creation of Windows EXEs on Linux ELF systems)

tar

minimal just install `tar`

unzip

natspec Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.

wimlib

fuse Use fuse libraries
iso Install app-cdr/cdrtools in order to prepare iso images
ntfs Use libntfs-3g library from sys-fs/ntfs3g
yasm Use yasm assembler instead of nasm

xz-utils

extra-filters Build additional filters that are not used in any of the default xz presets. This includes delta and BCJ coders, additional match finders and SHA256 checks.
pgo Optimize the build using Profile Guided Optimization (PGO)

zip

natspec Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.

app-backup

amanda

ndmp Support for the NDMP protocol
s3 Support for backing up to the Amazon S3 system
xfs Support for backing up raw XFS filesystems using xfsdump

backup-manager

s3 Support for backing up to the Amazon S3 system

bacula

bacula-clientonly Disable DB support, and just build a client
bacula-nodir Disable building of director
bacula-nosd Disable building of storage daemon
batch-insert Enable batch insert into data base
ipv6 Support IPV6 protocol"
logwatch Install support files for logwatch

bareos

ceph Enable sys-cluster/ceph support
clientonly Only install file-daemon (client)
director Install director
glusterfs Enable sys-cluster/glusterfs storage backend
jansson JSON API support using dev-libs/jansson for director
lmdb enable build of dev-db/lmdb support for faster accurate backup
logwatch Install support files for sys-apps/logwatch
ndmp Enable support for NDMP (Network Data Management Protocol)
scsi-crypto Enable low level SCSI crypto support
storage-daemon Install storage daemon (bareos-sd)
vmware Enable bareos-fd VMware plugin

btrbk

lsbtr Enable the lsbtr command-line tool
mbuffer Use sys-block/mbuffer to enable progress bar and buffering/limiting functionality

dar

argon2 Enable password hashing algorithm from app-crypt/argon2
dar32 Enables --enable-mode=32 option, which replace infinite by 32 bit integers
dar64 Enables --enable-mode=64 option, which replace infinite by 64 bit integers
gcrypt Enables strong encryption support
gpg Enables usage of asymmetric encryption algorithms
rsync Enables linking with net-libs/librsync for delta compression support

duplicity

s3 Support for backing up to the Amazon S3 system

rear

udev Have ReaR start backup when attaching your USB drive.

snapper

lvm Enable LVM thinprovisioned snapshots support sys-fs/lvm2
xattr Add support for getting and setting POSIX extended attributes, through sys-apps/attr.

tsm

tsm-cit IBM Tivoli Common Inventory Technology
tsm-hw Difference snapshot support for NetApp and N-Series file servers
vmware Install vmware data protection support

app-benchmarks

filebench

auto-completion Enable command-line autocompletion using dev-libs/libtecla

httperf

idleconn Build with the idleconn program

ioping

netdata Add support for netdata

ramspeed

pic Force shared libraries to be built as PIC (this is slower)

sysbench

aio Add support for AIO.
attachsql Add support for AttachSQL.
drizzle Add support for Drizzles.
largefile Add support for large files.

app-cdr

brasero

libburn Enable dev-libs/libburn backend
nautilus Build the gnome-base/nautilus extension
playlist Enable support for playlists through dev-libs/totem-pl-parser
tracker Enable audio playlist search using the app-misc/tracker indexer

cdemu

cdemu-daemon Pull app-cdr/cdemu-daemon dependency, useful in chroot environment (bug #315491). Do not disable until you know what you are doing.

dvdisaster

debug Enable memory debugging.

gaffitter

scripts Install additional gaffitter scripts for external programs

mirage2iso

pinentry Support app-crypt/pinentry password input backend.

app-containers

apptainer

network Install network plug-ins
suid Install SUID helper binary

buildah

btrfs Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.

containerd

btrfs Support for BTRFS snapshot driver
cri Support for Kubernetes CRI
device-mapper Support for device mapper snapshot driver

cri-o

btrfs Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
device-mapper Enables dependencies for the "devicemapper" graph driver, including necessary kernel flags.

crun

bpf Enable in Kernel, eBPF (enhanced Berkley Packet Filter) support for managing device controllers.
criu Enable CRIU based checkpoint/restore support

docker

btrfs Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
container-init Makes the a staticly-linked init system tini available inside a container.
device-mapper Enables dependencies for the "devicemapper" graph driver, including necessary kernel flags.
overlay Enables dependencies for the "overlay" graph driver, including necessary kernel flags.

docker-credential-helpers

pass Build pass helper for the pass utility.

lxc

io-uring Enable io_uring support, and use io_uring instead of epoll
lto Enable Link Time Optimization (LTO)
tools Build and install additional command line tools

podman

btrfs Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
cgroup-hybrid Use legacy (hybrid) cgroups instead of modern (unified) cgroups
fuse Enables fuse dependencies (fuse-overlayfs is especially useful for rootless mode).
init Enables catatonit dependency required for podman run --init.
rootless Enables dependencies for running in rootless mode.
wrapper Install wrapper which lets use podman for command `docker`

runc

kmem Enable Kernel Memory Accounting.

skopeo

btrfs Enables dependencies for the "btrfs" graph driver.
device-mapper Compiles with libdevmapper
rootless Compiles with libsubid

snapd

forced-devmode Automatically disable application confinement if feature detection fails.

app-crypt

aespipe

asm Enable assembly modules
cpu_flags_x86_padlock Use VIA padlock instructions, detected at run time, code still works on non-padlock processors

ccid

twinserial Enable twinserial reader

codecrypt

cryptopp Build algorithms that need Crypto++ support dev-libs/crypto++

dehydrated

cron Install cron job to sign/renew non-existent/changed/expiring certificates

eid-mw

dialogs Enable "askaccess" dialog box, by using x11-libs/gtk+
gtk All dialogs are available, by using x11-libs/gtk+
p11-kit Support for app-crypt/p11-kit.

ekeyd

minimal Only install the ekey-egd-linux service rather than the full ekeyd package.
munin Install a plugin for net-analyzer/munin to graph statistical data from ekeyd.
usb Build the libusb-based userland daemon for accessing the EntropyKey (alternative to the CDC USB driver). It is suggested to use this option by default, as the CDC driver in the kernel often seems to be fragile (or the gadget implementation on the EntropyKey is too buggy), and can cause various problems.

gnupg

smartcard Build scdaemon software. Enables usage of OpenPGP cards. For other type of smartcards, try app-crypt/gnupg-pkcs11-scd. Bring in dev-libs/libusb as a dependency; enable scdaemon.
tofu Enable support for Trust on First use trust model; requires dev-db/sqlite.
tools Install extra tools (including gpgsplit and gpg-zip).
tpm Enable TPM support via app-crypt/tpm2-tss and build tpm2d.
usb Build direct CCID access for scdaemon; requires dev-libs/libusb.
user-socket try a socket directory which is not removed by init manager at session end
wks-server Install the wks-server

gnupg-pkcs11-scd

proxy Build the gnupg-pkcs11-scd-prox

gpgme

common-lisp Install common-lisp files

hashcat

brain Enable the hashcat brain

heimdal

hdb-ldap Adds support for LDAP as a database backend
lmdb Add support for using dev-db/lmdb for lookup tables
otp Adds support for one-time passwords

ima-evm-utils

tpm Enable TPM support

johntheripper-jumbo

opencl Build with opencl/GPU cracking support
pcap Build with pcap support

keybase

fuse Enable app-crypt/kbfs support

kstart

afs Enables afs support which means you can acquire an afs token and set PAGs. It's recommended to set this USE if you need authenticated access to an AFS cell for your daemon/app.

libb2

native-cflags Use CFLAGS as determined by configure script. These flags will enable all CPU specific features it find available, to further optimise the implementation. This discards any existing CFLAGS set in make.conf or similar.

libsecret

tpm Enable Trusted Platform Module support via app-crypt/tpm2-tss

libu2f-host

systemd Use user ACLs rather than plugdev group to give user access to the HIDRAW device.

mit-krb5

doc Creates and installs the API and implementation documentation. This is only useful if you want to develop software which depends on kerberos
keyutils Enable for the keyring ccache using keyutils
lmdb Add support for using dev-db/lmdb for lookup tables
openldap Enable support for ldap as a database backend
pkinit Enable pkinit support for the initial ticket

mkp224o

pcre Search with a regex instead of prefix/suffix matching

ophcrack

tables Require the additional tables used to carry out cracking (app-crypt/ophcrack-tables)

ophcrack-tables

vistafree Installs the free Vista ophcrack tables
xpfast Installs the fast XP ophcrack tables
xpsmall Installs the small free XP ophcrack tables

pinentry

efl Build dev-libs/efl based pinentry

qca

botan Enable botan plugin
gcrypt Enable gcrypt plugin
gpg Enable GnuPG plugin
logger Enable logger plugin
nss Enable NSS plugin
pkcs11 Enable PKCS#11 plugin
sasl Enable SASL plugin
softstore Enable softstore plugin

seahorse

ldap Enable seahorse to manipulate GPG keys on a LDAP server.

swtpm

fuse Support sys-fs/fuse based /dev/tpm interface

tpm-tools

pkcs11 Build Token data management utilities based on OpenCryptoki's (dev-libs/opencryptoki) PKCS#11 implementation.

tpm2-pkcs11

fapi Enable feature API backend

tpm2-tools

fapi Enable feature API tools

tpm2-totp

plymouth Add sys-boot/plymouth support

tpm2-tss

fapi Enable feature API (requires openssl as crypto backend)
mbedtls Use net-libs/mbedtls as crypto engine
openssl Use dev-libs/openssl as crypto engine
policy Enable policy library (requires openssl as crypto backend)

veracrypt

asm Enable assembly for optimization

zulucrypt

kwallet Enable encrypted storage of passwords with kde-frameworks/kwallet
udev Whether udev will be consulted when deciding if a volume is system or not

app-dicts

aspell-be

classic Support classic spelling by default

gwaei

hunspell Enable app-text/hunspell spellchecking and morphological analysis
mecab Enable app-text/mecab support

myspell-pt

preao Use the pre ortographic agreement version of the dictionary

app-doc

csound-manual

html Install HTML documentation

devmanual

offline Use alternative minimal stylesheet instead of Tyrian theme

doxygen

clang support for sys-devel/clang assisted parsing
dot allow to create dot graphs using media-gfx/graphviz
doxysearch build doxyindexer and doxysearch.cgi

kicad-doc

html Generate documentation in HTML format
pdf Generate documentation in PDF format

linuxfromscratch

htmlsingle Install all-on-one-page HTML version.

pms

html Generate and install PMS as .html as well
twoside Enable two-sided layout suitable for printing

pms-bin

html Install PMS as .html as well

tldp-howto

html Install multi-chapter HTML docs
htmlsingle Install all-on-one-page HTML docs
pdf Install pdf docs
text Install plain-text docs

app-editors

bluefish

gucharmap Enable gucharmap dictionary plugin
spell Enable spell checking capabilities via enchant library

emacs

athena Enable the MIT Athena widget set (x11-libs/libXaw)
dynamic-loading Enable loading of dynamic libraries (modules) at runtime
games Support shared score files for games
gfile Use gfile (dev-libs/glib) for file notification
gmp Use the GNU multiple precision arithmetic library (dev-libs/gmp) instead of the bundled mini-gmp subset
gsettings Use gsettings (dev-libs/glib) to read the system font name
gzip-el Compress bundled Emacs Lisp source
harfbuzz Use media-libs/harfbuzz as text shaping engine
imagemagick Use media-gfx/imagemagick for image processing
jit Compile with Emacs Lisp native compiler support via libgccjit
json Compile with native JSON support using dev-libs/jansson
libxml2 Use dev-libs/libxml2 to parse XML instead of the internal Lisp implementations
mailutils Retrieve e-mail using net-mail/mailutils instead of the internal movemail substitute
small-ja-dic Generate a smaller-size Japanese dictionary (saves about 5 MiB in installed image)
source Install C source files and make them available for find-function
threads Add elisp threading support
toolkit-scroll-bars Use the selected toolkit's scrollbars in preference to Emacs' own scrollbars
tree-sitter Support the dev-libs/tree-sitter parsing library
wide-int Prefer wide Emacs integers (typically 62-bit). This option has an effect only on architectures where "long" and "long long" types have different size.
xwidgets Enable use of GTK widgets in Emacs buffers (requires GTK3)

fe

sendmail Send mail after editor abend

featherpad

X Link application against X11 libraries which adds support for virtual desktop awareness and tab DND

gedit-plugins

charmap Insert special characters just by clicking on them
git Shows document changes related to git's HEAD
terminal Embed a terminal in the bottom pane

gnome-latex

latexmk Install dev-tex/latexmk (used by default for the build tools)
rubber Install dev-tex/rubber (can be used for the build tools)

gvim

crypt Use dev-libs/libsodium for crypto support
cscope Enable cscope interface
netbeans Include netbeans external editor integration support
racket Enable support for Scheme using dev-scheme/racket

helix

grammar Build and install grammar language files

jasspa-microemacs

nanoemacs Build NanoEmacs instead of MicroEmacs

joe

xterm Enable full xterm clipboard support

leafpad

emacs Enable Emacs key theme

mousepad

shortcuts Build the "shortcuts" plugin

nano

debug Enable debug messages and assert warnings. Note that these will all be sent straight to stderr rather than some logging facility.
justify Enable justify/unjustify functions for text formatting.
magic Add magic file support (sys-apps/file) to automatically detect appropriate syntax highlighting
minimal Disable all fancy features, including ones that otherwise have a dedicated USE flag (such as spelling).

neovim

lto Build with Link Time Optimization (LTO)
nvimpager Install nvimpager symlink to less.sh macro

okteta

designer Build plugins for dev-qt/designer

pluma-plugins

bracketcompletion Auto complete bracket pairs
codecomment Comment code blocks
smartspaces Insert smart spaces
synctex Enable synctex support for pdflatex
terminal Embed a terminal in the bottom pane

qhexedit2

gui Install Qt5 hex editor

tea

aspell Enable spellchecking using app-text/aspell
hunspell Enable spellchecking using app-text/hunspell
qml Enable support for plugins using QML

vim

X Link console vim against X11 libraries to enable title and clipboard features in xterm
crypt Use dev-libs/libsodium for crypto support
cscope Enable cscope interface
racket Enable support for Scheme using dev-scheme/racket
terminal Enable terminal emulation support
vim-pager Install vimpager and vimmanpager links

vis

tre more memory efficient regex search using dev-libs/tre

xemacs

athena Chooses the MIT Athena widget set
bignum Support for OpenSSL bignum implementation
dnd Enables support for the x11-libs/dnd drag-n-drop library
eolconv Support detection and translation of newline conventions
mule Add multi-language support to XEmacs
pop Support POP for mail retrieval
xim Enable X11 XiM input method

app-emacs

auctex

preview-latex Use bundled preview-latex

bbdb

tex Install plain TeX support files
vm Add support for app-emacs/vm
wanderlust Add support for app-emacs/wanderlust

calfw

howm Add support for the app-emacs/howm note-taking tool

elscreen

wanderlust Include support for app-emacs/wanderlust

emacs-common

games Support shared score files for games
gsettings Install schema file for gsettings (dev-libs/glib)

emacs-w3m

gzip-el Compress bundled Emacs Lisp source

magit

libgit Use libgit (app-emacs/libegit2)

mu-cite

bbdb Include support for app-emacs/bbdb

org-mode

odt-schema Install non-free schema files for OpenDocument Text exporter

remember

bbdb Include support for app-emacs/bbdb
planner Include support for app-emacs/planner

slime

xref Install xref.lisp cross-referencing tool

sly

xref Install xref.lisp cross-referencing tool

vm

bbdb Include support for app-emacs/bbdb

wanderlust

bbdb Include support for app-emacs/bbdb

wikipedia-mode

outline-magic Enable support for outline-mode extensions (app-emacs/outline-magic)

app-emulation

86Box

dinput Enable legacy Dinput mode instead of Xinput for older controllers.
experimental Enable hardware from devbranch, which may be unstable or unusable.
fluidsynth Enable MIDI support through media-sound/fluidsynth.
munt Enable MIDI MT-32 support through media-libs/munt-mt32emu.
new-dynarec Enable new dynamic recompiler from PCem 15, which should provide an even better emulation speed.

aranym

clipboard Enable bidirectional clipboard transfer between the host and FreeMiNT
jit Build Just-In-Time compiler variant with increased performance
lilo Enable support for directly booting kernels such as Linux
osmesa Allow images to be rendered in memory using the host CPU
pmmu Build full PMMU variant, required for running mainline Linux
standard Build standard (no JIT or PMMU) variant

bochs

3dnow Enable support for emulating 3DNow! instructions (incomplete)
avx Enable support for emulating Advanced Vector Extensions (AVX)
debugger Enable debugger (slows down emulation)
gdb Enable support for the remote GDB stub
x86-64 Enable support for emulation of 64-bit CPUs

crossover-bin

capi Enable ISDN support via CAPI
opencl Enable OpenCL support
osmesa Add support for OpenGL in bitmaps using libOSMesa
pcap Support packet capture software (e.g. wireshark)

dosemu

fluidsynth use media-sound/fluidsynth for MIDI emulation

dxvk

crossdev-mingw Use sys-devel/crossdev for the toolchain rather than dev-util/mingw64-toolchain (requires manual setting up)
d3d10 Enable support for DirectX 10 (d3d10.dll)
d3d11 Enable support for DirectX 11 (d3d11.dll)
d3d9 Enable support for DirectX 9 (d3d9.dll)
dxgi Enable support for the DirectX Graphics Infrastructure (dxgi.dll)

faudio

dumpvoices FAudio dumps buffer data to individual files with RIFF/XWMA headers, usable with players like ffplay/testxwma.

fs-uae

fmv Enable support for CD32 FMV (full motion video)
glew Enable support for The OpenGL Extension Wrangler Library (media-libs/glew)

fs-uae-launcher

lha Enable LHA archive support

fuse

backend-X Use X11 rendering backend
backend-fbcon Use framebuffer rendering backend
backend-gtk3 Use Gtk+ rendering backend
backend-sdl Use SDL rendering backend
backend-svga Use svgalib rendering backend
memlimit Add compile-time memory usage limiting

fuse-utils

gcrypt Use dev-libs/libgcrypt for low-level crypto of some features, including logfiles.

grub-xen-host

pvh Build an additional grub bin for pvh.

hyperd

libvirt Enable support for KVM via libvirt
xen Enable support for the Xen Hypervisor

libcacard

passthrough Enable smartcard passthrough support via sys-apps/pcsc-lite

libguestfs

erlang Build Erlang bindings
fuse Enable image mount support via sys-fs/fuse
inspect-icons Use media-gfx/icoutils for accessing/inspecting icon file within images
libvirt Use app-emulation/libvirt to manipulate VMs
systemtap Use dev-util/systemtap to inspect VM via "probes"

libspectrum

gcrypt Use dev-libs/libgcrypt for low-level crypto of some features, including logfiles.

libvirt

dtrace Enable dtrace support via dev-util/systemtap
firewalld DBus interface to iptables/ebtables allowing for better runtime management of your firewall.
fuse Allow LXC to use sys-fs/fuse for mountpoints
glusterfs Enable GlusterFS support via sys-cluster/glusterfs
iscsi Allow using an iSCSI remote storage server as pool for disk image storage
iscsi-direct Allow using libiscsi for iSCSI storage pool backend
libssh Use net-libs/libssh to communicate with remote libvirtd hosts, for example: qemu+libssh://server/system
libssh2 Use net-libs/libssh2 to communicate with remote libvirtd hosts, for example: qemu+libssh2://server/system
libvirtd Builds the libvirtd daemon as well as the client utilities instead of just the client utilities
lvm Allow using the Logical Volume Manager (sys-fs/lvm2) as pool for disk image storage
lxc Support management of Linux Containers virtualisation (app-containers/lxc)
nfs Allow using Network File System mounts as pool for disk image storage
numa Use NUMA for memory segmenting via sys-process/numactl and sys-process/numad
openvz Support management of OpenVZ virtualisation (openvz-sources)
parted Allow using real disk partitions as pool for disk image storage, using sys-block/parted to create, resize and delete them.
pcap Support auto learning IP addreses for routing
qemu Support management of QEMU virtualisation (app-emulation/qemu)
rbd Enable rados block device support via sys-cluster/ceph
virt-network Enable virtual networking (NAT) support for guests. Includes all the dependencies for NATed network mode. Effectively any network setup that relies on libvirt to setup and configure network interfaces on your host. This can include bridged and routed networks ONLY if you are allowing libvirt to create and manage the underlying devices for you. In some cases this requires enabling the 'netcf' USE flag (currently unavailable).
virtualbox Support management of VirtualBox virtualisation (app-emulation/virtualbox)
wireshark-plugins Build the net-analyzer/wireshark plugin for the Libvirt RPC protocol
xen Support management of Xen virtualisation (app-emulation/xen)
zfs Enable ZFS backend storage sys-fs/zfs

nemu

network-map Adds possibility of exporting network map to SVG
ovf Adds support for OVA/OVF import
remote-api Adds API for remote control
spice Adds Spice protocol support
vnc-client Adds support for external VNC client

open-vm-tools

deploypkg Build deploypkg plugin
dnet Enable support for nicinfo
doc Generate API documentation
fuse Enable vmblock-fuse/vmhgfs-fuse
gtkmm Compile with Gtkmm and sigc++ (Recommended)
multimon Enable multimon (Requires X)
resolutionkms Build the linux/unix resolutionkms module
vgauth Build vgauth

pcem

networking Enable support for emulation of network cards.

punes

cg Add support for Nvidia CG Toolkit

q4wine

ico Enable ico support via media-gfx/icoutils
iso Support unprivileged mounting of ISO9660 images via sys-fs/fuseiso
wineappdb Enable Wine AppDB browser support

qemu

accessibility Adds support for braille displays using brltty
aio Enables support for Linux's Async IO
alsa Enable alsa output for sound emulation
bpf Enable eBPF support for RSS implementation.
capstone Enable disassembly support with dev-libs/capstone
curl Support ISOs / -cdrom directives via HTTP or HTTPS.
fdt Enables firmware device tree support
fuse Enables FUSE block device export
glusterfs Enables GlusterFS cluster fileystem via sys-cluster/glusterfs
gnutls Enable TLS support for the VNC console server. For 1.4 and newer this also enables WebSocket support. For 2.0 through 2.3 also enables disk quorum support.
io-uring Enable efficient I/O via sys-libs/liburing.
iscsi Enable direct iSCSI support via net-libs/libiscsi instead of indirectly via the Linux block layer that sys-block/open-iscsi does.
jemalloc Enable jemalloc allocator support
jpeg Enable jpeg image support for the VNC console server
keyutils Support Linux keyrings via sys-apps/keyutils
multipath Enable multipath persistent reservation passthrough via sys-fs/multipath-tools.
ncurses Enable the ncurses-based console
nfs Enable NFS support
numa Enable NUMA support
pin-upstream-blobs Pin the versions of BIOS firmware to the version included in the upstream release. This is needed to sanely support migration/suspend/resume/snapshotting/etc... of instances. When the blobs are different, random corruption/bugs/crashes/etc... may be observed.
pipewire Enable pipewire output for sound emulation
plugins Enable qemu plugin API via shared library loading.
png Enable png image support for the VNC console server
pulseaudio Enable pulseaudio output for sound emulation
rbd Enable rados block device backend support, see https://docs.ceph.com/en/mimic/rbd/qemu-rbd/
sdl Enable the SDL-based console
sdl-image SDL Image support for icons
slirp Enable TCP/IP in hypervisor via net-libs/libslirp
spice Enable Spice protocol support via app-emulation/spice
ssh Enable SSH based block device support via net-libs/libssh2
static Build the User and Software MMU (system) targets as well as tools as static binaries
static-user Build the User targets as static binaries
systemtap Enable SystemTAP/DTrace tracing
usb Enable USB passthrough via dev-libs/libusb
usbredir Use sys-apps/usbredir to redirect USB devices to another machine over TCP
vde Enable VDE-based networking
vhost-net Enable accelerated networking using vhost-net, see https://www.linux-kvm.org/page/VhostNet
virgl Enable experimental Virgil 3d (virtual software GPU)
virtfs Enable VirtFS via virtio-9p-pci / fsdev. See https://wiki.qemu.org/Documentation/9psetup
vte Enable terminal support (x11-libs/vte) in the GTK+ interface
xattr Add support for getting and setting POSIX extended attributes, through sys-apps/attr. Requisite for the virtfs backend.
xen Enables support for Xen backends

runv

libvirt Enable support for KVM via libvirt
xen Enable support for the Xen Hypervisor

ski

debug enable extra binary emulation debugging via sys-libs/binutils-libs

spice

smartcard Enable smartcard remoting using app-emulation/libcacard

uade

fuse Enable sys-fs/fuse uadefs frontend for on-the-fly WAV conversion

vice

ethernet Enable ethernet emulation
headless Include the headless variant of the emulator
mpg123 Enable mp3@64 cartridge support
parport Enable parallel port SID support
pci Enable PCI device discovery using sys-apps/pciutils

virt-manager

policykit Enables sys-auth/polkit authentication support, required when using app-emulation/libvirt with PolicyKit authentication
sasl Depend on the proper libraries needed to connect to SASL-enabled libvirtd instances (e.g. Kerberos-protected instances).

virt-viewer

libvirt Support connecting to virtual machines managed by libvirt.
spice Support connecting to SPICE-enabled virtual machines.
vnc Support connecting to VNC-enabled virtual machines.
vte Enable terminal support (x11-libs/vte) in the GTK+ interface

virt-what

dmi Use sys-apps/dmidecode to read firmware data

virtualbox

dtrace Install dtrace Extension Pack
headless Build without any graphic frontend
lvm Build VBoxVolInfo that needs devicemapper from sys-fs/lvm2.
pax-kernel Apply patch needed for pax enabled kernels.
sdk Enable building of SDK
udev Controls installation of special USB udev rules.
vboxwebsrv Build and install the VirtualBox webservice
vde Support for VDE networking via net-misc/vde

vkd3d

spirv-tools Enable SPIRV shader debugging support using dev-util/spirv-tools

vkd3d-proton

crossdev-mingw Use sys-devel/crossdev for the toolchain rather than dev-util/mingw64-toolchain (requires manual setting up)
extras Install extra tools and demos in /usr/lib/vkd3d-proton

wine-gecko

shared Install pre-unpacked files which do not need to be copied into the Wine prefix

wine-mono

shared Install pre-unpacked files which do not need to be copied into the Wine prefix

wine-proton

crossdev-mingw Use sys-devel/crossdev for the toolchain rather than dev-util/mingw64-toolchain (requires manual setting up)
gecko Enable mshtml support using app-emulation/wine-gecko
mono Enable .NET support using app-emulation/wine-mono
osmesa Enable off-screen rendering (OpenGL in bitmaps) support
perl Install helpers that require perl (winedump/winemaker)
sdl Enable gamepad support using media-libs/libsdl2
vkd3d Enable DirectX 12 support using app-emulation/vkd3d

wine-staging

capi Enable ISDN support using net-libs/libcapi
crossdev-mingw Use sys-devel/crossdev for the toolchain rather than dev-util/mingw64-toolchain (requires manual setting up)
dos Pull in games-emulation/dosbox to run DOS applications
gecko Enable mshtml support using app-emulation/wine-gecko
mingw Build PE files using a MinGW toolchain for better compatibility
mono Enable .NET support using app-emulation/wine-mono
netapi Enable support for configuring remote shares using net-fs/samba
opencl Enable OpenCL support
osmesa Enable off-screen rendering (OpenGL in bitmaps) support
pcap Support packet capture software (e.g. wireshark)
perl Install helpers that require perl (winedump/winemaker)
samba Pull in net-fs/samba with winbind for NTLM auth support
sdl Enable gamepad support using media-libs/libsdl2
wow64 Enable running 32bit applications without 32bit ELF multilib by mapping to 64bit calls (experimental/WIP, USE=abi_x86_32 is recommended for complete support)

wine-vanilla

capi Enable ISDN support using net-libs/libcapi
crossdev-mingw Use sys-devel/crossdev for the toolchain rather than dev-util/mingw64-toolchain (requires manual setting up)
dos Pull in games-emulation/dosbox to run DOS applications
gecko Enable mshtml support using app-emulation/wine-gecko
mingw Build PE files using a MinGW toolchain for better compatibility
mono Enable .NET support using app-emulation/wine-mono
netapi Enable support for configuring remote shares using net-fs/samba
opencl Enable OpenCL support
osmesa Enable off-screen rendering (OpenGL in bitmaps) support
pcap Support packet capture software (e.g. wireshark)
perl Install helpers that require perl (winedump/winemaker)
samba Pull in net-fs/samba with winbind for NTLM auth support
sdl Enable gamepad support using media-libs/libsdl2
vkd3d Enable DirectX 12 support using app-emulation/vkd3d
wow64 Enable running 32bit applications without 32bit ELF multilib by mapping to 64bit calls (experimental/WIP, USE=abi_x86_32 is recommended for complete support)

winetricks

rar Pull in app-arch/unrar for extraction of rar-compressed game files

x48

readline Enables support for libreadline

xe-guest-utilities

xenstore Use xenstore binaries bundled by Citrix instead of building app-emulation/xen-tools

xen

boot-symlinks Symlink xen.gz variants in /boot, disable on fat filesystems
efi Adds efi boot support, requires LDFLAG -melf_x86_64 for amd64
flask Enable the Flask XSM module from NSA

xen-tools

api Build the C libxenapi bindings
hvm Enable support for hardware based virtualization (VT-x,AMD-v)
ipxe Enable ipxe support
ovmf Enable support to boot UEFI guest vm, needed by hvm
pygrub Install the pygrub boot loader
qemu Enable IOEMU support via the use of qemu-dm
qemu-traditional Build the old qemu traditional device model (useful only if you cannot change to the new device model e.g. Windows VMs)
rombios Enable rombios support, needed by ipxe
screen Enable support for running domain U console in an app-misc/screen session
system-ipxe Using sys-firmware/ipxe instead of the bundled one
system-qemu Using app-emulation/qemu instead of the bundled one
system-seabios Using sys-firmware/seabios instead of the bundled one

xtrs

ls-dos Install LS-DOS disk images for Model 4P

app-eselect

eselect-php

fpm Enable the FastCGI Process Manager SAPI

eselect-wine

xdg Set XDG_DATA_DIRS to use the selected wine.desktop, allows e.g. 'xdg-open my.exe' for file managers

app-forensics

afflib

fuse Enable extra fuse thingies
qemu Enable qemu stuff
s3 Enable support for Amazon S3

aide

curl Use curl for http,https and ftp backends
e2fs Enable support for checking file attributes on ext2/ext3/ext4 filesystems

chkrootkit

cron Install cron script for weekly rootkit scans

honggfuzz

clang Enable clang support (pull sys-libs/blocksruntime dependency).

libewf

bfio Enables libbfio for chaining file in file handling
fuse Enable fuse support for ewfmount
uuid Enable UUID support in the ewftools

lynis

cron Install /etc/cron.* files

sleuthkit

aff Enable extra aff formats
ewf Enable libewf support

volatility3

crypt support plugins that decrypt passwords, password hashes, etc.
disasm support plugins that perform malware analysis and disassemble code
jsonschema improve error messages regarding improperly configured ISF files
leechcore support memory acquisition via leechcore
snappy support AVMLs native compression format
yara support YARA pattern matching engine

yara

cuckoo Enable cockoo module
dex Enable dex module
dotnet Enable dotnet module
macho Enable macho module
magic Enable magic module
profiling Enable rules profiling
python Pulls in python binding via dev-python/yara-python

app-i18n

fcitx

autostart Enable XDG-compatible autostart of Fcitx
enchant Enable Enchant backend (using app-text/enchant) for spelling hinting
gtk2 Install input method module for GTK+ 2
gtk3 Install input method module for GTK+ 3
opencc Enable OpenCC engine (using app-i18n/opencc) for converter between Simplified Chinese and Traditional Chinese
pango Enable support for x11-libs/pango
table Install table input methods for Simplified Chinese
xkb Enable support for XKB (required for fcitx-xkb, fcitx-xkbdbus, part of fcitx-keyboard)

fcitx-libpinyin

dictionary-manager Install dictionary manager

fcitx-rime

configuration_tool Install configuration tool

fcitx-unikey

macro-editor Install macro editor

freewnn

uum Build uum

ibus

emoji Enable support for Emoji
gtk2 Enable the GTK-2 input method module
gtk3 Enable the GTK-3 input method module
gtk4 Enable the GTK-4 input method module
unicode Enable support for Unicode choice

ibus-handwrite

zinnia Enable support for app-i18n/zinnia

ibus-libpinyin

boost Compile against dev-libs/boost libraries
opencc Enable support for app-i18n/opencc

ibus-pinyin

boost Enable support for dev-libs/boost

im-chooser

xfce Enable support for XFCE panel

imsettings

xfconf Enable support for xfce-base/xfconf

librime

debug Enable debugging (including logging of input of RIME input methods)

mozc

fcitx4 Enable support for app-i18n/fcitx 4
gui Install graphical user interface tool (mozc_tool)
ibus Enable support for app-i18n/ibus
renderer Enable native candidate window

pyzy

boost Enable support for dev-libs/boost
doc Generate API documentation
opencc Enable support for app-i18n/opencc

rime-data

extra Install extra packages

scim

gtk3 Enable support for x11-libs/gtk+:3

scim-anthy

gtk3 Enable support for x11-libs/gtk+:3
kasumi Use Anthy dictionary maintenance tool (app-dicts/kasumi)

tomoe

hyperestraier Enable support for app-text/hyperestraier

uim

anthy Enable support for app-i18n/anthy
eb Enable support for dev-libs/eb
gtk2 Enable support for x11-libs/gtk+:2
skk Enable support for app-i18n/skk-jisyo

app-laptop

hdapsd

libconfig Require dev-libs/libconfig to allow the daemon to read a configuration file at startup

ibam

gkrellm Enable building of app-admin/gkrellm module

laptop-mode-tools

apm Add APM (Advanced Power Management) support

pbbuttonsd

ibam Enable support for Intelligent Battery Monitoring
macbook Enable support for the Macbook and Macbook Pro

thinkfan

atasmart include libatasmart support to get disc temperature
nvidia allow thinkfan to read GPU temperature from the proprietary nVidia driver
yaml use YAML format for config file

tp_smapi

hdaps Install a compatible HDAPS module

app-metrics

collectd

contrib Install user-contributed files in the doc directory
filecaps When set collectd daemon will have set required capabilities to run most plugins even if run as unprivileged user
java Must be set (workaround for java-pkg-opt-2 eclass limitation) when you want java or genericjmx plugin
udev Enable optional udev usage in disk plugin; Required for smart plugin
xfs Enable optional capability to filter on XFS file system in df plugin; Requires XFS headers from sys-fs/xfsprogs

node_exporter

systemd Enables systemd collector by default

prometheus-podman-exporter

btrfs Collect metrics for btrfs filesystem

app-misc

FreeSSM

small-resolution Build the app for small resolution screeens

blink1

mini-tool Build and install command-line mini-tool blink1-mini-tool (normally used for embedded devices)
server Build and install REST API server (currently hard-coded to TCP port 8080)
tool Build and install command-line tool blink1-tool

broot

X X11 clipboard interaction

byobu

screen Use app-misc/screen as the default backend

ca-certificates

cacert Include root/class3 certs from CAcert (https://www.cacert.org/)

carbon-c-relay

lz4 add support for LZ4 compressed transport
oniguruma use dev-libs/oniguruma as regex implementation
pcre2 use dev-libs/libpcre2 as regex implementation
snappy add support for Snappy compressed transport

ddccontrol

pci enable direct PCI memory access (the setuid ddcpci util)

ddcutil

drm Use x11-libs/libdrm for more verbose diagnostics.
usb-monitor Adds support for monitors attached via USB.
user-permissions Adds a udev rules to allow non-root users in the i2c group to access the /dev/i2c-* devices. If usb-monitor is selected, users will need to be added to the video group to access the USB monitor. Otherwise, only root will be able to use ddcutil.

digitemp

ds2490 Build support for the ds2490 sensor
ds9097 Build support for the ds9097 sensor
ds9097u Build support for the ds9097u sensor

fastfetch

chafa Enables text/graphics renderer with media-gfx/chafa
ddcutil Use app-misc/ddcutil to query monitor settings
opencl Enables OpenCL support
osmesa Enables offscreen rendering support from media-libs/mesa
pci Enables reading GPU via sys-apps/pciutils
vulkan Enables reading GPU via media-libs/vulkan-loader
xfce Enables support for XFCE config
xrandr Enables support for Xrandr

g810-led

hidapi Use dev-libs/hidapi instead of virtual/libusb for talking to the device (advertised to be faster)

geoclue

modemmanager Enable geolocation through 3G or GPS enabled hardware through net-misc/modemmanager.
zeroconf Enable retrieval of GPS location from Android devices with https://wiki.gnome.org/Apps/GeoclueShare

gramps

geo Enable rendering of geographical data using sci-geosciences/osm-gps-map
rcs Adds support for family tree archives via dev-vcs/rcs
reports All external software that is needed for graphical reports will be installed

graphlcd-base

fontconfig Add support for media-libs/fontconfig font names.
freetype Add support for media-libs/freetype.
graphicsmagick Add support for media-gfx/graphicsmagick.
imagemagick Add support for media-gfx/imagemagick.

irtrans-irserver

mono Enable mono support

jdupes

dedupe Enable deduplication support

jp

jpp Install jpp which is an extended superset of the jp CLI for JMESPath

jpipe

jp-symlink Install a jp symlink that points to jpipe.
jpp-symlink Install a jpp symlink that points to jpipe.

jq

oniguruma Use dev-libs/oniguruma for regular expression support

kryoflux-dtc

demos Install example floppy game files.
fast-firmware Install fast firmware instead of slow firmware.

lcd4linux

apm Enable the APM plugin.
asterisk Enable the Asterisk plugin.
button-exec Enable the Button plugin, to execute something on keypress.
cpuinfo Enable the cpuinfo plugin.
dbus Enable the dbus plugin.
diskstats Enable the diskstats plugin.
dmalloc Enable dmalloc for debugging.
dvb Enable support for the DVB plugin.
event Enable the event plugin.
exec Enable the exec plugin, to read output from external programs.
fifo Enable the FIFO (First-In, First-Out) plugin.
file Enable the file plugin, to read from input from files.
gps Enable the gps plugin, for reading gps coordinates.
hddtemp Enable the hddtemp plugin, to read from the hddtemp daemon.
huawei Enable the huawei plugin, to read from a huawei device.
i2c-sensors Enable the i2c_sensors plugin, to read sensor data.
iconv Enable the iconv plugin, to convert between encodings.
isdn Enable the isdn plugin, to get information about ISDN.
kvv Enable the kvv plugin, to get realtime train schedule from the Karlsruher Verkehrsverbund.
loadavg Enable the loadavg plugin, to get stats load
meminfo Enable the meminfo plugin, to get memory statistics.
mpd Enable the mpd plugin, to read from the Music Player Daemon.
mpris-dbus Enable the mpris plugin, to read data via dbus for mpris.
mysql Enable the mysql plugin, to get mysql database information.
netdev Enable the netdev plugin, to get interface statistics.
netinfo Enable the netinfo plugin, to get more interface statistic.
outb Enable raw i/o access.
pop3 Enable the pop3 plugin, to get notified about new mails.
proc-stat Enable the proc_stat plugin, to read data from the proc file system.
python Enable support for dev-lang/python and enable the python plugin, to execute own python scripts.
qnaplog Enable the qnaplog plugin, to read a log from a QNAP device.
raspi Enable the raspi plugin, to read sensor data from a Raspberry Pi.
sample Enable the sample plugin.
statfs Enable the statfs plugin, to get statistics about the file system.
uname Enable the uname plugin, to get the output of uname.
uptime Enable the uptime plugin.
w1retap Enable the w1retap plugin.
wireless Enable the wireless plugin, to get wireless statistics.

lcdproc

ethlcd Enable support for ethlcd in the hd44780 driver.
extra-charmaps Enable extra language specific charmaps.
menu Enable menu support in the lcdproc client.
nfs Display NFS filesystem stats in the lcdproc client.
png Enable support for media-libs/libpng in the glcd driver.
samba Display SMBFS filesystem stats in the lcdproc client.
test-menu Enable test menu support for the lcdproc server.
truetype Enable support for media-libs/freetype in the glcd driver.

libdatovka

openssl Use openssl backend

lirc

audio Support using an audio device connected to an IR receiver
devinput Support the devinput input device
ftdi Support FTDI devices
gtk Include GTK support which enables the use of lirc-setup
inputlirc Add a dependency on app-misc/inputlircd
uinput Enable support for uinput

mc

edit Compile and install the mcedit application
sftp Add support for sftp (uses net-libs/libssh2 for it).
slang Use sys-libs/slang instead of sys-libs/ncurses.

mime-types

nginx Enable mime-types support for www-servers/nginx package

mosquitto

bridge Enable bridge support in the MQTT broker.
persistence Store messages and subscriptions to a file.
srv Include SRV lookup support.
websockets Support the WebSocket protocol.

muttprint

doc Builds documentation

neofetch

X Enable support for detecting DEs, WMs, screen resolutions, and showing images from an X terminal

nnn

8contexts Enable 8 contexts (instead of 4)
colemak Key bindings for Colemak keyboard layout
colemak-dh Key bindings for Colemak-DH keyboard layout
emoji Display icons using emoji
gitstatus Add git status column to the detail view
icons Display icons using icons-in-terminal
namefirst Print filenames first in the detail view
nerdfonts Display icons using nerdfonts icons
qsort Use Alexey Tourbin's quick sort implementation
restorepreview Add pipe to close and restore preview-tui for internal undetached edits

note

general Add support for ascii flatfile backend
text Add support for text backend

ola

ftdi Support FTDI devices
http Enable built-in Web UI
rdm-tests Install RDM responder tests

pax-utils

python Install a more powerful/faster version of lddtree

recoll

camelcase Enable indexing for camelCase sentences and words
chm Enable CHM file support via dev-python/pychm
inotify Use the Linux Kernel notification subsystem for monitoring file alterations in realtime
session Stop monitoring file alterations when X11 session terminates
webengine Use dev-qt/qtwebengine for fancy result list display

rlwrap

debug Enable debug

screen

multiuser Enable multiuser support (by setting correct permissions)
nethack Express error messages in nethack style

screenfetch

X Use the media-gfx/scrot package to take screenshots

skim

tmux Install sk-tmux script to run skim in a tmux pane
vim Install vim plugin for skim

sphinx

id64 use 64-bit document and word IDs
mariadb Add mariadb database support
stemmer Enable language stemming support

task

sync Enable "task sync" support

tmux

utempter Include libutempter support

tracker

miners Install the app-misc/tracker-miners package for actual data mining support for tracker
stemmer Add word stemming via dev-libs/snowball-stemmer.

tracker-miners

cue Enable cue sheet parsing
gsf Enable gnome-extra/libgsf based data extractor and for ODT.
iptc Enable extraction of IPTC data from pictures
iso Enable extraction of metadata from ISO disk images
playlist Add support for playlists
xps Add support for XPS file format through app-text/libgxps.

unfoo

minimal Do not install all support archive binaries

vcontrold

vclient Build the vclient helper program to talk to vcontrold
vsim Build the vsim helper program (simulates the heating's answers, for development and debugging)

vifm

developer Enable features of interest to developers
extended-keys Support for extended keys (arrows, home etc)
gtk Use gtk+ to determine mimetypes
vim Install the vifm vim plugin and vim-compatible documentation

worker

avfs Enable support for sys-fs/avfs

app-mobilephone

gammu

curl Enables curl support
irda Enables infrared support
mysql Use mysql for data storage
nls Enable native language support
odbc Use ODBC as DB connector
postgres Use PostgreSQL for data storage
usb Enable USB suport

gnokii

ical Enable support for dev-libs/libical
irda Enable infrared support
pcsc-lite Enable smartcard support with sys-apps/pcsc-lite
sms Enable SMS support (build smsd)

scrcpy

lto Build with Link Time Optimization (LTO)

smstools

stats Enable statistic reporting

app-office

abiword

collab Enable collaborative editing plugin
goffice Enable goffice plugin
grammar Enable grammar checking via dev-libs/link-grammar
map Enable world map support through media-libs/libchamplain
math Enable support for x11-libs/gtkmathview
ots Enable Text Summarizer plugin
plugins Enable plugins build (see http://www.abisource.com/wiki/PluginMatrix for more information). If your file cannot be opened due lack of support, try enabling this.
redland Enables support redland and raptor libs.
thesaurus Enable thesaurus support
wordperfect Enable wordperfect file support via app-text/libwpd

calcurse

caldav Support CalDAV

calligra

activities Enable kactivities support
charts Build chartshape plugin for creating business charts with dev-libs/kdiagram
gemini Enable tablet and 2:1 devices support
import-filter Enable support for various import filter file formats like WordPerfect, Visio and Apple Keynote
lcms Build colorengine plugins using media-libs/lcms
okular Enable bindings for kde-apps/okular
phonon Build stage/eventplugins and videoshape plugin using media-libs/phonon
spacenav Enable support for the 3Dconnexion spacenav input device via dev-libs/libspnav

calligraplan

activities Enable kactivities support
holidays Enable kde-frameworks/kholidays integration
kwallet Enable access to encrypted OpenDocument files with kde-frameworks/kwallet storage

glabels

barcode Enable barcode support through external libraries.

gnucash

aqbanking Connect to some internet banks via AqBanking
quotes Enable online stock quote retrieval
register2 Use the new register (Experimental)

gnumeric

libgda Enable database support through gnome-extra/libgda.
perl Enable perl plugin loader.

grisbi

goffice enable goffice graphic support

kexi

experimental Enable features deemed experimental by upstream
marble Enable displaying of maps using kde-apps/marble
mdb Enable support for Microsoft Access database

kmymoney

activities Enable kde-frameworks/kactivities integration
addressbook Enable kde-apps/akonadi contact integration
hbci Enable HBCI support using net-libs/aqbanking
holidays Enable kde-frameworks/kholidays integration

kraft

pim Enable support for KDE PIM resources integration

libalkimia

webengine Enable online quotes using dev-qt/qtwebengine

libreoffice

base Enable full support for LibreOffice Base databases (involves additional bundled libs)
clang Use Clang compiler instead of GCC
coinmp Use sci-libs/coinor-mp as alternative solver
googledrive Enable support for remote files on Google Drive
mariadb Prefer mariadb connector over mysql connector
odk Build the Office Development Kit
pdfimport Enable PDF import via the Poppler library
vulkan Enable Vulkan usage via the skia library (clang recommended)

libreoffice-l10n

offlinehelp Install help files locally instead of using the LibreOffice Wiki

lyx

aspell Add support for aspell spellchecking
dia Add support for diagrams (app-office/dia)
dot Add support for DOT import (media-gfx/graphviz)
enchant Add support for enchant spellchecking wrapper (both aspell and hunspell can be used by LyX).
gnumeric Add support for importing Gnumeric/OpenOffice/MS Excel spreadsheets into LyX.
html Add support for HTML import
hunspell Add support for spellchecking based on hunspell and reuse system-wide OpenOffice dictionaries. This also enable thesaurus dictionaries not accessible via aspell.
monolithic-build This should speed up compilation significantly when you have enough RAM (> 600 MB)
rcs Add support for revision control via dev-vcs/rcs
rtf Add support for RTF import/export packages

magicpoint

contrib Install additional contributed scripts

mdbtools

glib Use functions provided by dev-libs/glib, not built-in

planner

libgda PostgreSQL support via gnome-extra/libgda

sc-im

X Use x11-misc/xclip for clipboard copy/paste
ods Add ods import support
plots Add sci-visualization/gnuplot for plotting support
tmux Use app-misc/tmux for clipboard copy/paste
wayland Use gui-apps/wl-clipboard for clipboard copy/paste
xls Add xls support
xlsx Add xlsx support

scribus

boost Enable support for Boost based enhancement
hunspell Enable support for spell checking with app-text/hunspell
minimal Don't install headers (only required for e.g. plug-in developers)
osg 3D rendering via dev-games/openscenegraph
scripts Install the scripts
templates Document templates
tk Install tk based scripts e.g. FontSample.py

skrooge

activities Enable kactivities support

texmacs

netpbm Add support for media-libs/netpbm

texstudio

video Use phonon for video embedding

app-pda

gtkpod

clutter Enable clutter support for displaying coverart

app-portage

conf-update

colordiff Use colors when displaying diffs (app-misc/colordiff)

eix

debug Build with upstream's CXXFLAGS/LDFLAGS for debugging support; not recommended for normal use.
doc Create description of the eix cache file additionally in html format
sqlite Compile in support for portage's sqlite backend; to actually use it you need additional configuration of portage and eix

g-sorcery

bson Support BSON file format for package DB

gemato

gpg Install dependencies needed for OpenPGP signature verification support
pretty-log Pull dev-python/rich to enable pretty logs
tools Install additional utilities (benchmarks, hash testing tools, fast Manifest generators) to /usr/share/gemato.

grs

server Install all the tools building systems

hackport

profile Enable profiling flags

kuroneko

scraper Include the dependencies necessary for Bugzilla scraping.

nattka

depgraph-order Process packages in depgraph order whenever possible.

pfl

network-cron Adds a cron job which does a weekly submit of the package database

portage-utils

qmanifest Build qmanifest applet, this adds additional dependencies for GPG, OpenSSL and BLAKE2B hashing
qtegrity Build qtegrity applet, this adds additional dependencies for OpenSSL

tatt

templates Install template scripts to be used with tatt

app-shells

atuin

client Enable the autin client
server Enable the autin server
sync Enable the server-sync feature in the autin client

autojump

ipython Add support for dev-python/ipython

bash

bashlogger Log ALL commands typed into bash; should ONLY be used in restricted environments such as honeypots
mem-scramble Build with custom malloc/free overwriting allocated/freed memory
net Enable /dev/tcp/host/port redirection
pgo Optimize the build using Profile Guided Optimization (PGO)
plugins Add support for loading builtins at runtime via 'enable'

bash-completion

eselect Support blacklisting of completions via 'eselect bashcomp'. This enables custom Gentoo patching of upstream completion loader.

mksh

lksh variant that uses POSIX-compliant arithmetics with the host “long” data type and is automatically in POSIX mode when called as /bin/sh

nushell

dataframe Dataframe feature for nushell
extra Enable less stable or less common commands

pdsh

rsh This allows the use of rsh (remote shell) and rcp (remote copy) for authoring websites. sftp is a much more secure protocol and is preferred.

shish

diet Use dev-libs/dietlibc

app-text

atril

caja Enable property page extension in mate-base/caja
dvi Enable build-in DVI viewer
epub Enable build-in DVI viewer using net-libs/webkit-gtk
synctex Enable search highlighting through synctex (virtual/tex-base)
t1lib Enable the Type-1 fonts for the build-in DVI viewer (media-libs/t1lib)
xps Enable XPS viewer using app-text/libgxps

blogc

git Build blogc-git-receiver tool
httpd Build blogc-runserver tool
make Build blogc-make tool

calibre

font-subsetting Enable font subsetting support
speech Enable text-to-speech support
system-mathjax Use a system copy of mathjax
unrar Enable support for comic books compressed with the non-free Rar format

crengine-ng

chm Support chm format
fribidi Support bidirectional text by dev-libs/fribidi
harfbuzz Use media-libs/harfbuzz for kerning and ligatures
libunibreak Use dev-libs/libunibreak for hyphenation
libutf8proc Use dev-libs/libutf8proc for manipulating unicode strings
lto Use link time optimization

crm114

mew Add support for using the mewdecode mime decoder (app-emacs/mew)
normalizemime Add support for using the normalizemime (mail-filter/normalizemime)

crqt-ng

chm Support chm format
fribidi Support bidirectional text by dev-libs/fribidi
harfbuzz Use media-libs/harfbuzz for kerning and ligatures
libunibreak Use dev-libs/libunibreak for hyphenation
libutf8proc Use dev-libs/libutf8proc for manipulating unicode strings

crwx-ng

chm Support chm format
fribidi Support bidirectional text by dev-libs/fribidi
harfbuzz Use media-libs/harfbuzz for kerning and ligatures
libunibreak Use dev-libs/libunibreak for hyphenation
libutf8proc Use dev-libs/libutf8proc for manipulating unicode strings

dblatex

inkscape Use inkscape to convert SVG. Disable to use gnome-base/librsvg instead.

dictd

judy Build Judy-based (dev-libs/judy) plugin implementing fast "exact" and especially "lev" strategies
minimal Don't build server but dict client, dictzip and dictfmt only.

docbook-sgml-utils

jadetex Add support for processing tex files produced by the TeX backend of Jade

docbook-xsl-ns-stylesheets

ruby Install the Ruby-based dbtoepub script; requires an interpreter compatible with app-eselect/eselect-ruby.

docbook-xsl-stylesheets

ruby Install the Ruby-based dbtoepub script; requires an interpreter compatible with app-eselect/eselect-ruby.

ebook-tools

lit2epub Install lit2epub script

editorconfig-core-c

cli Install command line interface.

enchant

aspell Adds support for app-text/aspell spell checker
hunspell Adds support for app-text/hunspell spell checker
nuspell Adds support for app-text/nuspell spell checker
voikko Adds support for dev-libs/libvoikko spell checker

evince

dvi Enable the built-in DVI viewer
nautilus Enable property page extension in gnome-base/nautilus
postscript Enable support for PostScript and Adobe Illustrator documents with app-text/libspectre
spell Enable inline spell check for annotations via app-text/gspell
xps Enable XPS viewer using app-text/libgxps

foliate

handy Use gui-libs/libhandy

ghostscript-gpl

unicode Add support for unicode passwords via net-dns/libidn

groonga

abort Enable query abortion
benchmark Build benchmark programs
dynamic-malloc-change Allow dynamic memory allocation change for testing
exact-alloc-count Atomic counting for memory alloc count
fmalloc Make memory allocation failed in specified condition for debug
futex Use futex
libevent Enable dev-libs/libevent used for suggestion
mecab Use app-text/mecab for morphological analysis
msgpack Enable dev-libs/msgpack used for suggestion
nfkc Use nfkc based utf8 normalization
sphinx Enable document generation by app-misc/sphinx
uyield Build for detecting race conditions
zeromq Enable net-libs/zeromq used for suggestion

htmltidy

deprecated Install tools and header files which are now considered deprecated

hyperestraier

mecab Enable app-text/mecab support for Estraier

kbibtex

webengine Use dev-qt/qtwebengine for HTML previews

kjots

speech Enable text-to-speech support

lcdf-typetools

kpathsea Enable integration with kpathsea search library (TeX related)

libebook

tools Build file conversion tools

libgepub

webkit Build with GepubWidget based on Webkit

libmwaw

tools Build file conversion tools

libqxp

tools Build file conversion tools

libstaroffice

tools Build conversion tools
zlib Enable support for compressed data

libwpd

tools Build file conversion tools

libwps

tools Build file conversion tools

mandoc

cgi build man.cgi web plugin for viewing man pages
system-man set as the default man provider

mathtex

png Generate png images by default instead of gif

msort

heap Use heap instead of alloca()
icu Use dev-libs/icu instead of dev-libs/libutf8proc.
libuninum Use dev-libs/libuninum for conversion.

mupdf

drm Enable support for Digital rights management (DRM)

pandoc

embed-data-files Embed data files in binary for relocatable executable.
trypandoc Build trypandoc cgi executable.

pandoc-bin

pandoc-symlink Install pandoc symlink that points to pandoc-bin

pandoc-cli

lua Support custom modifications and conversions with the pandoc Lua scripting engine.
nightly Add '-nightly-COMPILEDATE' to the output of '--version'.
server Include support for running pandoc as an HTTP server.

pdfgrep

unac Removing accents and ligatures before search

pdfpc

gstreamer Compile support for movie playback (media-libs/gstreamer)
soup Compile support for REST server (net-libs/libsoup)
webkit Enable viewing Markdown notes (net-libs/webkit-gtk)

pelican

markdown Markdown support

podofo

boost Add support for boost
tools Build and install commandline tools.

poppler

boost Use boost::small_vector for a serious performance gain
gpgme Enable signatures handling with app-crypt/gpgme
nss Enable signatures handling with dev-libs/nss
utils Install command-line PDF converters and various utilities.

qpdfview

fitz Use experimental fitz rendering, provided by app-text/mupdf, instead of poppler
synctex Add support for searching TeX sources

robodoc

examples Installs usage examples in /usr/share for Perl

sdcv

darkterm Improve readability of color output on terminals with dark background.

sigil

plugins Installed needed Python packages for using Sigil plugins

sword

clucene Use dev-cpp/clucene for lucene search support

tessdata_best

osd Enable support orientation and script detection.

tessdata_fast

osd Enable support orientation and script detection.

tessdata_legacy

math Enable support for recognition of equations.
osd Enable support orientation and script detection.

tesseract

float32 Support float for model training and text recognition (faster, requires less RAM)
opencl Enable opencl support for speedup using GPU computation.
training Install training applications to add support for new languages.

texlive

context Add support for the ConTeXt format (dev-texlive/texlive-context)
extra Add support for extra TeXLive packages
games Add typesetting support for games (chess, etc.) (dev-texlive/texlive-games)
graphics Add support for several graphics packages (pgf, tikz,...)
humanities Add LaTeX support for the humanities (dev-texlive/texlive-humanities)
luatex Add extra support for luatex
metapost Add support for metapost: A tool for creating graphics in scalable PostScript
music Add support for music typesetting (dev-texlive/texlive-music)
pdfannotextractor Add dev-tex/pdfannotextractor support, for extracting annotations from PDF files
pstricks Add pstricks packages (dev-texlive/texlive-pstricks)
publishers Add support for publishers (dev-texlive/texlive-publishers)
science Add typesetting support for natural and computer sciences (dev-texlive/texlive-mathscience)
tex4ht Add support for dev-tex/tex4ht (for converting (La)TeX to (X)HTML, XML and OO.org)
texi2html Add support for app-text/texi2html which converts texi files to HTML
xetex Add support for XeTeX macros (dev-texlive/texlive-xetex)

texlive-core

luajittex Add support for LuaJitTeX: LuaTeX based on LuaJIT which is usually faster.
xetex Add support for XeTeX: a TeX system with Unicode and modern font technologies.
xindy Add support for Xindy: A general-purpose index processor.

wdiff

experimental Build experimental utilities (mdiff, unify, wdiff2)

webgen

builder Enable programmatic HTML/XML generation
highlight Enable syntax highlighting for certain plugins
markdown Markdown support

writerperfect

abiword Add support for abiword format using app-text/libabw
ebook Add support for various ebook formats using app-text/libebook
epub Add support for conversion to ePub format using app-text/libepubgen
freehand Add support for freehand format using media-libs/libfreehand
gsf Add support for structured files using gnome-extra/libgsf
keynote Add support for keynote format using app-text/libetonyek
mspub Add support to mspub format using app-text/libmspub
mwaw Add support to mwaw formats using app-text/libmwaw
pagemaker Add support to pagemaker formats using media-libs/libpagemaker
qxp Add support for QuarkXpress documents using app-text/libqxp
visio Add support for visio format using media-libs/libvisio
wpd Add support for wpd format using app-text/libwpd
wpg Add support for wpg format using app-text/libwpg
wps Add support for wps format using app-text/libwps
zmf Add support for Zoner Callisto/Draw documents format using media-libs/libzmf

wv

tools Install optional utilities considered deprecated in favor of using AbiWord.

xmlto

text Support conversion from XML to plain text

xpdf

cmyk Include support for CMYK rasterization
i18n Enable support non-UTF8 national charsets
icons Generate desktop PNG icons using media-gfx/inkscape
libpaper Use app-text/libpaper to get paper preferences
metric Use A4 instead of US Letter paper size by default for PostScript output. This option has effect only if libpaper USE flag is disabled
opi Include support for OPI (Open Prepress Interface) comments
textselect Allow text selection
utils Install command-line PDF converters and various utilities

zathura

synctex Use libsynctex to get latex codeline from pdf

zathura-meta

cb Install plug-in for ComicBook support

app-vim

gentoo-syntax

ignore-glep31 Remove GLEP 31 (UTF-8 file encodings) settings

app-xemacs

xemacs-packages-all

mule Add multi-language support to XEmacs

dev-ada

aws

shared Build shared library
wsdl Used to convert ada to wsdl

gnatcoll-bindings

shared Build shared library
static-pic Build shared library

gnatcoll-core

shared Build shared library
static-pic Build static library with pic code

gnatcoll-db

db2ada Build gnatcoll_db2ada
gnatinspect Build gnatinspect
shared Build shared library
sql Build sql library
static-pic Build shared library
xref Build xref library

gpr

shared Build shared library
static-pic Build static library with pic code

gpr-unit-provider

shared Build shared library
static-pic Build static library with pic code

gtkada

shared Build gtkada as shared library
static-pic Build static library with pic code

langkit

shared Build shared library
static-pic Build static library with pic code

libadalang

static-pic Build static library with pic code

libadalang-tools

shared Build shared library
static-pic Build static library with pic code

libgpr

shared Build shared library
static-pic Build static library with pic code

spawn

glib Add support to dev-libs/glib-based mainloop.
shared Build shared library
static-pic Build static library with pic code

templates-parser

shared Build shared library

xmlada

shared Build shared library
static-pic Build static library with pic code

dev-cpp

abseil-cpp

cxx17 Build with -DCMAKE_CXX_STANDARD=17 (required by some revdeps)

benchmark

lto Optimize the build using Link Time Optimization (LTO)

eigen

cuda Build with cuda support

glog

gflags Use dev-cpp/gflags for flag parsing
libunwind Use libunwind library (sys-libs/libunwind or sys-libs/llvm-libunwind) instead of built-in fallback implementation for stack unwinding

jwt-cpp

picojson Enable use of dev-cpp/picojson

libcmis

tools Build client tool for testing and viewing features

libjson-rpc-cpp

http-client Build support for HTTP client using net-misc/curl
http-server Build support for HTTP server using net-libs/libmicrohttpd
redis-client Build support for Redis client using dev-libs/hiredis
redis-server Build support for Redis server using dev-libs/hiredis
stubgen Build header stub code generator (needed for development and when pregenerated headers are not bundled)

msgpack-cxx

boost Enable boost support

opentelemetry-cpp

jaeger Include the jaeger exporter
prometheus include the Prometheus Client in the SDK

sdbus-c++

systemd Use external libsystemd instead of statically-linked build
tools Install interface stub code generator

dev-db

etcd

server Installs etcd daemon

firebird

server Install the server components of Firebird, not just the client
xinetd Install ClassicServer

mariadb

backup Build mariadb-backup which supports SST and hot backup of InnoDB, Aria and MyISAM including compression and encryption
columnstore Build the ColumnStore storage engine
extraengine Add support for alternative storage engines (Archive, CSV, Blackhole, Federated(X), Partition)
galera Enables galera replication
innodb-lz4 Enables lz4 compression methods for InnoDB/XtraDB
innodb-lzo Enables lzo compression methods for InnoDB/XtraDB
innodb-snappy Enables snappy compression methods for InnoDB/XtraDB using app-arch/snappy
jdbc Enable the CONNECT engine to access foreign databases via JDBC
latin1 Use LATIN1 encoding instead of UTF8
mroonga Add support for the Mroonga engine for interfacing with the Groonga text search
numa Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
oqgraph Add support for the Open Query GRAPH engine
pam Enable the optional PAM authentication plugin for the server
profiling Add support for statement profiling (requires USE=community).
rocksdb Add support for RocksDB; a key/value, LSM database optimized for flash storage
s3 Build the S3 storage engine
server Build the server program
sphinx Add suport for the sphinx full-text search engine
sst-mariabackup Add tools needed to support the mariabackup SST method
sst-rsync Add tools needed to support the rsync SST method
systemtap Build support for profiling and tracing using dev-util/systemtap
test Install upstream testsuites for end use.
yassl Enable SSL connections and crypto functions using the bundled yaSSL

mongodb

lto Adds support for link time optimization
mongosh Install the MongoDB shell from app-admin/mongosh-bin
tools Install the MongoDB tools (mongoimport, mongodump...) from app-admin/mongo-tools

mycli

ssh Add support for connection over SSH tunnel

mysql

cjk Add CJK support for InnoDB fulltext search using app-text/mecab
client-libs Build the client libraries from the server package instead of the C Connector packages (not recommended)
experimental Build experimental features aka "rapid" plugins
latin1 Use LATIN1 encoding instead of UTF8
numa Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
profiling Add support for statement profiling (requires USE=community).
router Build the MySQL router program
server Build the server program
systemtap Build support for profiling and tracing using dev-util/systemtap
test Install upstream testsuites for end use.

mysql-connector-c++

legacy Build the legacy 1.x API as well as the DevX API

oracle-instantclient

jdbc Support for XA, Internationalization, and RowSet operations under JDBC
odbc Libraries for enabling ODBC applications
precomp "proc" binary and related files to precompile a Pro*C application
sdk Header files and an example makefile for developing Oracle applications
sqlplus The SQL*Plus command line tool for SQL and PL/SQL queries
tools Data Pump, SQL*Loader and Workload Replay Client

percona-server

cjk Add CJK support for InnoDB fulltext search using app-text/mecab
latin1 Use LATIN1 encoding instead of UTF8
numa Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
profiling Add support for statement profiling (requires USE=community).
rocksdb Add support for RocksDB; a key/value, LSM database optimized for flash storage
router Build the MySQL router program
server Build the server program
tokudb Add support for TokuDB storage engine
tokudb-backup-plugin Builds the TokuDB backup plugin

pgbouncer

c-ares Use c-ares as the DNS backend instead of evdns (libevent).
udns Use udns as the DNS backend instead of evdns (libevent). Supports IPv4 only.

pgpool2

memcached Use memcached for query caching.

phpmyadmin

setup Installs the phpMyAdmin setup utility. Users who don't use the utility should disable this USE flag for security reasons as the setup tool was the target of various exploits in the past.

postgis

address-standardizer Normalize US and CA postal addresses
gtk Build graphical interface for shp2pgsql (shp2pgsql-gui)
topology Build topology spatial types and functions

postgresql

llvm Add support for llvm JIT engine
server Disable to build and install the clients and libraries only.
uuid Enable server side UUID generation (via dev-libs/ossp-uuid).

psqlodbc

iodbc Use dev-db/libiodbc. Disable to use dev-db/unixODBC.

redis

tcmalloc Use tcmalloc from dev-util/google-perftools for allocations.

spatialite

geos Add the sci-libs/geos library for exact topological tests
proj Add the sci-libs/proj library for reprojection features
rttopo Add the sci-geosciences/librttopo library for topology support
xls Add the dev-libs/freexl library for xls import support

sqldeveloper

sybase Add support for the Sybase SQL Database Server

sqlite

secure-delete Enable overwriting of deleted content with zeros by default (http://sqlite.org/pragma.html#pragma_secure_delete), causing some performance penalty
tools Install additional tools, among which are included: sqlite3-analyzer, sqlite3-changeset, sqlite3-db-dump, sqlite3-diff, sqlite3-rbu, sqlite3-expert and others.

sqlitestudio

cli Build CLI interface

timescaledb

proprietary-extensions Enable proprietary features/extensions licensed under the TimeScale License

unixODBC

minimal Disable bundled drivers and extra libraries (most users don't need these)
odbcmanual Administrator, Internal Structure, Programmer and User documentation

dev-embedded

avrdude

ftdi Enable support for USB FTDI chips via dev-embedded/libftdi

libftdi

tools build ftdi_eeprom helper tool

openocd

capstone Use dev-libs/capstone for disassembly support
cmsis-dap Support for CMSIS-DAP compliant adapters
dummy Build the dummy port driver
ftdi Enable support for USB FTDI chips via dev-embedded/libftdi
jlink Build the SEGGER J-Link driver
parport Enable support for parport JTAG devices
verbose-io Verbose IO and comm JTAG and USB messages

sdcc

avr Add support for AVR -- not supported upstream
boehm-gc Enable Hans Boehm's garbage collector dev-libs/boehm-gc
device-lib Enable built of devices libraries
ds390 Add support for Dallas DS390
ds400 Add support for Dallas DS400
ez80-z80 Add support for EZ80-Z80
gbz80 Add support for Gameboy gbz80
hc08 Add support for Freescale/Motorola HC08 based
mcs51 Add support for Intel mcs51
mos6502 Add support for MOS 6502
mos65c02 Add support for MOS 65C02
non-free Enable non-free runtime library parts
packihx Enable Intel HEX files pack utility
pdk13 Add support for PDK13
pdk14 Add support for PDK14
pdk15 Add support for PDK15
pdk16 Add support for PDK16
pic14 Add support for Microchip 14 bits PICs
pic16 Add support for Microchip 16 bits PICs
r2k Add support for Rabbit 2000
r2ka Add support for Rabbit 2000A
r3ka Add support for Rabbit 3000A
s08 Add support for Freescale/Motorola S08
sdbinutils Enable SDCC library archive utilities sdar, sdranlib, sdnm
sdcdb Enable SDCC source level debugger
sdcpp Enable SDCC preprocessor based on GCC cpp
sm83 Add support for Gameboy SM83
stm8 Add support for STMicroelectronics STM8
tlcs90 Add support for TLCS-90
ucsim Enable software simulator for microcontrollers
z180 Add support for Zilog Z180
z80 Add support for Zilog Z80
z80n Add support for Zilog Z80N

u-boot-tools

envtools Build only the target-side environment tools

urjtag

ftd2xx Enable support for USB FTDI chips via dev-embedded/libftd2xx
ftdi Enable support for USB FTDI chips via dev-embedded/libftdi

dev-games

cegui

devil Build the DevIL based ImageCodec module
freeimage Build the FreeImage based ImageCodec module
irrlicht Enable the Irrlicht renderer
ogre Enable the OGRE renderer
tinyxml Enable the Tiny XML parser module
xerces-c Enable the Xerces-C++ XML parser module
zip Enable the Minizip resource provider

godot

bullet Enable the sci-physics/bullet module
deprecated Enable support for deprecated features
raycast Enable the raycast Editor module using media-libs/embree
runner Build an additional binary optimized for running games (only relevant with USE=tools)
speech Enable text-to-speech support
tools Enable the Godot Editor for game development
webm Enable the WebM module

guichan

allegro Build the Allegro frontend

mygui

l10n_ru Install some additional russian docs if 'doc' useflag enabled
ogre Use the ogre render subsystem. (cannot combine with opengl)
opengl Use the opengl render subsystem. (cannot combine with ogre)
plugins Build MyGUI plugins
samples Install MyGUI demos (needs ogre USE flag)
tools Build the tools for development

ode

double-precision more precise calculations at the expense of speed
gyroscopic enable gyroscopic term (may cause instability)

ogre

assimp Use media-libs/assimp to import assets from 3D files
boost Enable boost support
bullet Use sci-physics/bullet for physics plugin
cache Enable GL state cache support
cg NVIDIA toolkit plugin
deprecated Build deprecated nodeless positioning of Lights and Cameras.
double-precision More precise calculations at the expense of speed
egl Use egl instead of glx
fine-granularity Enable fine light mask granularity. This impacts on performance and should not be enabled unless an application really needs it.
freeimage Support images via media-libs/freeimage
gl3plus Build OpenGL 3+ RenderSystem
gles2 Build OpenGL ES 2.x RenderSystem
gles3 Enable OpenGL ES 3.x Features
json Use dev-libs/rapidjson (needed by Hlms JSON materials)
legacy-animations Use the skeletal animation from 1.x. It's much slower, but the new system is still experimental.
ois Pull in Object-oriented Input System library dev-games/ois for samples
poco When USE=threads, use poco for threading
resman-pedantic Resource Manager PEDANTIC : require an explicit resource group. Case sensitive lookup. Some demos might not work with this setting. (default: case-insensitive + sensitive lookup in all groups)
tbb When USE=threads, use tbb for threading
tools Build and install AssimpConverter (assimp USE flag is enabled), MeshUpgrader, VRMLConverter and XMLConverter

openscenegraph

collada Enable DAE file support via dev-libs/collada-dom
dicom Enable DICOM medical image file support via sci-libs/dcmtk
egl Enable EGL support
fox Build examples using x11-libs/fox library
gdal Enable support for sci-libs/gdal library
las Enable support for geospatial data LAS LiDAR format using sci-geosciences/liblas
openinventor Build OpenInventor plugin
osgapps Build osg applications
sdl2 Use media-libs/libsdl2 additionally to media-libs/libsdl
xrandr Enable support for the X xrandr extension

openscenegraph-openmw

collada Enable DAE file support via dev-libs/collada-dom
dicom Enable DICOM medical image file support via sci-libs/dcmtk
egl Enable EGL support
fox Build examples using x11-libs/fox library
gdal Enable support for sci-libs/gdal library
las Enable support for geospatial data LAS LiDAR format using sci-geosciences/liblas
openinventor Build OpenInventor plugin
osgapps Build osg applications
sdl2 Use media-libs/libsdl2 additionally to media-libs/libsdl
xrandr Enable support for the X xrandr extension

physfs

7zip Enable 7zip/lzma archive support
grp Enable Build Engine GRP archive support
hog Enable Descent I/II HOG archive support
iso Enable ISO9660 file support
mvl Enable Descent I/II MVL archive support
qpak Enable Quake I/II QPAK archive support
slb Enable Independence War SLB archive support
vdf Enable Gothic/Gothic II VDF archive support
wad Enable Doom WAD archive support

simgear

dns Enable DNS resolver via net-libs/udns
gdal Enable alternative terrain engine based on pagedLOD via sci-libs/gdal
subversion Enable terrasync scenery downloader

dev-haskell

abstract-deque

usecas Enable the reference implementation to use hardware compare-and-swap.

aeson

cffi Controls whether to include c-ffi bits or pure haskell. Default to False for security.
ordered-keymap Use ordered @Data.Map.Strict@ for KeyMap implementation.

aeson-pretty

executable build/install the command-line tool as well as the library
lib-only don't build 'aeson-pretty' executable.

ansi-terminal

example Build the example application

assoc

tagged You can disable the use of the `tagged` package using `-f-tagged`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

atomic-primops

debug Enable extra internal checks.

bifunctors

semigroups You can disable the use of the `semigroups` package using `-f-semigroups`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
tagged You can disable the use of the `tagged` package using `-f-tagged`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

bitvec

gmp Link against the GMP library for the ultimate performance of `zipBits`, `invertBits` and `countBits`. Users are strongly encouraged to enable this flag whenever possible.

boring

tagged You can disable the use of the `tagged` package using `-f-tagged`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

c2hs

regression Enable regression suite build.

cabal-install

lukko Use @lukko@ for file-locking
native-dns Enable use of the [resolv](https://hackage.haskell.org/package/resolv) & [windns](https://hackage.haskell.org/package/windns) packages for performing DNS lookups

cairo

svg Build the Scalable Vector Graphics (SVG) backend of Cairo.

chell

color-output use colors in program output

citeproc

executable Build citeproc executable
icu Use Haskell bindings to the ICU library

cmdargs

examples Build the cmdargs-demo program
quotation Build the Quote module
testprog Build the test program

comonad

indexed-traversable You can disable the use of the `indexed-traversable` package using `-f-indexed-traversable`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `FunctorWithIndex`

contravariant

semigroups You can disable the use of the `semigroups` package using `-f-semigroups`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
statevar You can disable the use of the `StateVar` package using `-f-StateVar`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
tagged You can disable the use of the `tagged` package on older versons of GHC using `-f-tagged`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

criterion

embed-data-files Embed the data files in the binary for a relocatable executable. (Warning: This will increase the executabl size significantly.)

crypto-api

all-cpolys Build all the CMAC polynomes up to 10000 bits instead of just the usual ones

cryptohash-sha256

executable Build the cryptohash-sha256sum executable

crypton

check-alignment extra check on alignment in C layers, which cause lowlevel assert errors. for debugging only.
integer-gmp Whether or not to use GMP for some functions
old-toolchain-inliner use -fgnu89-inline to workaround an old compiler / linker / glibc issue.
support-aesni allow compilation with AESNI on system and architecture that supports it
support-deepseq add deepseq instances for cryptographic types
support-pclmuldq Allow compilation with pclmuldq on architecture that supports it
support-rdrand allow compilation with RDRAND on system and architecture that supports it
support-sse Use SSE optimized version of (BLAKE2, ARGON2)
target-attributes use GCC / clang function attributes instead of global target options.

cryptonite

integer-gmp Whether or not to use GMP for some functions
target-attributes use GCC / clang function attributes instead of global target options.

dlist

werror Enable -Werror

doctest-driver-gen

executable Build the doctest-driver-gen executable

entropy

donotgetentropy Avoid use of the getentropy() *nix function. By default getentropy will be used if detected during compilation (this plays poorly with cross compilation).
halvm Build for the HaLVM.

foldable1-classes-compat

tagged You can disable the use of the `tagged` package using `-f-tagged`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

foundation

experimental Enable building experimental features, known as highly unstable or without good support cross-platform

glib

closure-signals Use the the GClosure-based signals implementation.

gtk2hs-buildtools

closuresignals Use the the GClosure-based signals implementation.

hackage-security

lukko Use @lukko@ for file-locking, otherwise use @GHC.IO.Handle.Lock@

hashable

random-initial-seed Randomly initialize the seed on every executable invocation. This is not a security feature and is intended only for testing (it can affect legitimate use cases).

hashtables

bounds-checking if on, use bounds-checking array accesses
detailed-profiling add detailed profiling information to profiled build-depends

haskeline

terminfo Use the terminfo package for POSIX consoles.

hdbc-sqlite3

splitbase Choose the new smaller, split-up package.

hslua-cli

executable Compile `hslua` standalone executable.

hslua-repl

executable Compile `luarepl` standalone executable.

hsyaml

exe Enable @exe:yaml-test@ component

http-api-data

text-show Use text-show library for efficient ToHttpApiData implementations.

httpd-shed

buildexamples Build example executables.

juicypixels

mmap Enable the file loading via mmap (memory map)

libyaml

system-libyaml Use the system-wide libyaml instead of the bundled copy
unicode Enable unicode output. Otherwise, unicode characters will be escaped.

lpeg

rely-on-shared-lpeg-library Do not build lpeg from source, but trust that lpeg is made available in other ways, e.g., through a system-wide installation. The loader will be replaced with a placeholder function that only emits a message.

lua

system-lua Use @pkg-config@ to discover library and include paths. Setting this flag implies `pkg-config`.

markdown-unlit

executable Build executable

monad-logger

template-haskell Enable Template Haskell support

monad-par

chaselev Use Chase-Lev Deques for higher-perf work-stealing.

nats

binary enable binary instances
hashable enable hashable instances
template-haskell enable template_haskell

network

devel using tests for developers

nothunks

bytestring Provide instances for bytestring
text Provide instances for text
vector Provide instances for vector

pandoc

embed-data-files Embed data files in binary for relocatable executable.

parsec-numbers

parsec1 use dev-haskell/parsec1 instead of dev-haskell/parsec

parsers

attoparsec You can disable the use of the `attoparsec` package using `-f-attoparsec`.
binary You can disable the use of the `binary` package using `-f-binary`.
parsec You can disable the use of the `parsec` package using `-f-parsec`.

persistent-sqlite

build-sanity-exe Build a sanity check test executable

prettyprinter

buildreadme Build the readme generator
text While it's a core value of @prettyprinter@ to use @Text@, there are rare circumstances (mostly when @prettyprinter@ arises as a dependency of test suites of packages like @bytestring@ or @text@ themselves) when this is inconvenient. In this case one can disable this flag, so that @prettyprinter@ fallbacks to @String@.

quickcheck

template-haskell Build Test.QuickCheck.All, which uses Template Haskell.

quickcheck-classes

aeson You can disable the use of the `aeson` package using `-f-aeson`. This may be useful for accelerating builds in sandboxes for expert users.
binary-laws Include infrastructure for testing class laws of binary type constructors. It is required that this flag match the value that the `unary-laws` flag was given when building `quickcheck-classes-base`. Disabling `unary-laws` while keeping `binary-laws` enabled is an unsupported configuration.
semigroupoids You can disable the use of the `semigroupoids` package using `-f-semigroupoids`. This may be useful for accelerating builds in sandboxes for expert users.
semirings You can disable the use of the `semirings` package using `-f-semirings`. This may be useful for accelerating builds in sandboxes for expert users.
unary-laws Include infrastructure for testing class laws of unary type constructors. It is required that this flag match the value that the `unary-laws` flag was given when building `quickcheck-classes-base`.
vector You can disable the use of the `vector` package using `-f-vector`. This may be useful for accelerating builds in sandboxes for expert users.

quickcheck-classes-base

binary-laws Include infrastructure for testing class laws of binary type constructors. Disabling `unary-laws` while keeping `binary-laws` enabled is an unsupported configuration.
unary-laws Include infrastructure for testing class laws of unary type constructors.

random-bytestring

pcg compile with support for PCG from pcg-random

sandi

conduit Build with conduit

semialign

semigroupoids Build with semigroupoids dependency

sha

exe Build a sha1 and a sha384 executable similar to 'md5sum'.

shelly

lifted run the tests against Shelly.Lifted

simple-sendfile

allow-bsd Allow use of BSD sendfile (disable on GNU/kFreeBSD)

skein

big-endian When manually selecting the endianness, use big-endian (default is little-endian).
force-endianness Use a manually selected endian when compiling (see flag 'big-endian').
reference Use the reference implementation instead of the optimized one.

skylighting

executable Whether to build the skylighting program

skylighting-core

executable Build skylighting-extract tool

some

newtype-unsafe Use implementation using @newtype@ and unsafe @Any@, instead of GADT

splitmix

optimised-mixer Use JavaScript for mix32

tasty

clock Depend on the clock package for more accurate time measurement

texmath

executable Compile test executable.
server Compile webserver.

text-short

debug Enable runtime-checks via 'assert'

tls

compat Accept SSLv2 client hello for beginning SSLv3 / TLS handshake
network Use the base network library

transformers-base

orphaninstances Build instances for orphan datatypes.

typst

executable Compile executable to be used in testing and development.

unicode-collation

doctests Run doctests as part of test suite. Use with: @--write-ghc-environment-files=always@.
executable Build the unicode-collate executable.

unix-compat

old-time build against old-time package

vector

boundschecks Enable bounds checking
internalchecks Enable internal consistency checks at the cost of a significant performance penalty
unsafechecks Enable bounds checking in unsafe operations at the cost of a significant performance penalty

vector-algorithms

bench Build a benchmarking program to test vector-algorithms performance
boundschecks Enable bounds checking
internalchecks Enable internal consistency checks at the cost of a significant performance penalty.
properties Enable the quickcheck tests
unsafechecks Enable bounds checking in unsafe operations at the cost of a significant performance penalty.

void

safe dissable effective but unsafe coersions

wai-app-static

print print debug info.

warp

allow-sendfilefd Allow use of sendfileFd (not available on GNU/kFreeBSD)
x509 Adds a dependency on the x509 library to enable getting TLS client certificates.

wcwidth

cli Enable command line tool

yaml

executable Install the yaml2json and json2yaml executables

yesod-form

network-uri Get Network.URI from the network-uri package

zip-archive

executable Build the Zip executable.

zlib

bundled-c-zlib Use the bundled zlib C sources. Requires pkg-config to be False. For windows, this is the default.
non-blocking-ffi The (de)compression calls can sometimes take a long time, which prevents other Haskell threads running. Enabling this flag avoids this unfairness, but with greater overall cost.

dev-java

ant

antlr Enable ANTLR Ant tasks
bcel Enable bcel (bytecode manipulation) Ant tasks
bsf Enable support for Apache Bean Scripting Framework (dev-java/bsf)
commonslogging Enable commons-logging Ant tasks
commonsnet Enable commons-net Ant tasks
jai Enable JAI (Java Imaging) Ant task
javamail Enable JavaMail Ant task
jdepend Enable Jdepend Ant tasks
jmf Enable JMF (Java Media Framework) Ant tasks
jsch Disable Jsch (ssh, scp and related) Ant tasks
junit Enable JUnit Ant tasks
junit4 Enable JUnit4 Ant tasks
junitlauncher Enable JUnit5 Ant tasks
log4j Enable Apache log4j Ant tasks
oro Enable Apache Oro Ant tasks
regexp Enable Apache Regexp Ant tasks
resolver Enable Apache Resolver Ant tasks
swing Enable Swing Ant tasks
testutil Enable optional test util classes
xz Enable XZ Ant tasks

commons-logging

log4j Add optional support for log4j

dom4j

jaxen Includes org.jaxen.dom4j package

eclipse-ecj

ant Support using ecj in Ant builds via dev-java/ant-eclipse-ecj

emma

launcher Install /usr/bin/emma. Collides with sci-biology/emboss.

icedtea

cacao Use the CACAO virtual machine rather than HotSpot.
cups Link against the CUPS library at compile time, rather than using it dynamically at runtime.
headless-awt Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
jamvm Use the JamVM virtual machine rather than HotSpot.
jbootstrap If possible, recompile the final IcedTea executables with itself.
kerberos Link against Kerberos in order to obtain the cache location.
pax-kernel Apply patch needed for pax enabled kernels.
pch Build using pre-compiled headers.
sctp Build the SCTP NIO channel implementation against lksctp
shenandoah Include the Shenandoah ultra-low pause time garbage collector (-XX:+UseShenandoahGC) (arm64 and x86_64 only)
smartcard Build the PCSC driver against pcsc-lite
system-lcms Build against the system LCMS installation rather than the in-tree copy.
zero Enable Zero assembler port (usually for non-HotSpot architectures)

icedtea-bin

headless-awt Don't install the X backend for AWT, needed by some GUIs (used to be X flag)

java-config

compat Install bin/java-config-2 symlink pointing to java-config

jaxen

dom4j Includes org.jaxen.dom4j package
jdom Includes org.jaxen.jdom package
xom Includes org.jaxen.xom package

junit

migration-support Include the junit-jupiter-migrationsupport module, which helps with migration from JUnit 4 to JUnit Jupiter
suite Include the JUnit Platform Suite Engine, which adds test suite support
vintage Include JUnit Vintage, which allows JUnit 5 to run JUnit 3 and JUnit 4 tests

openjdk

headless-awt Don't install the X backend for AWT, needed by some GUIs
javafx Import OpenJFX modules at build time, via dev-java/openjfx
jbootstrap Build OpenJDK twice, the second time using the result of the first
lto Enable Link Time Optimization (LTO)
source Install JVM sources
system-bootstrap Bootstrap using installed openjdk
systemtap Enable SystemTAP/DTrace tracing

openjdk-bin

headless-awt Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
source Install JVM sources

openjdk-jre-bin

headless-awt Don't install the X backend for AWT, needed by some GUIs (used to be X flag)

openjfx

media Compile media module, based on gstreamer-minimal (does not pull gstreamer)
source Install JavaFX sources

pdfbox

tools Build and install pdfbox-tools

protobuf-java

system-protoc Use protoc provided by dev-libs/protobuf

rxtx

lfd Installs and uses LockFileServer daemon (lfd)

sbt

binary Install from (Gentoo-compiled) binary instead of building from sources. Set this when you run out of memory during build.

dev-lang

R

lto Use link-time optimization for R and its recommended packages.

algol68g

mpfr Add support for multiprecision floating point rouding

ammonite-repl-bin

scala2-13 Install Ammonite for Scala 2.13
scala3-0 Install Ammonite for Scala 3.0
scala3-1 Install Ammonite for Scala 3.1
scala3-2 Install Ammonite for Scala 3.2

bas

lr0 Use the LR0 parser instead of the recursive descending parser

crystal

debug Build each module as a separate object file. Speeds build up.

erlang

kpoll Enable kernel polling support

gdl

eigen Build matrix manipulation with dev-cpp/eigen
glpk Use GNU Linear Programming Kit sci-mathematics/glpk
gshhs Add support for projection adn continent maps with sci-geosciences/gshhs-data
hdf Add support for the Hierarchical Data Format v.4
proj Add support for sci-libs/proj (geographic projections)
shapelib Add support for manipulating ESRI Shapefiles with sci-libs/shapelib
udunits Add support for manipulating units of physical quantities

gforth

check Enable build-time sanity check.

ghc

binary Install the binary version directly, rather than using it to build the source version.
elfutils Enable DWARF-based backtraces using dev-libs/elfutils.
ghcbootstrap Internal: Bootstrap GHC from an existing GHC installation.
ghcmakebinary Internal: Build binary friendly for redistribution.
gmp Use dev-libs/gmp for integer operations (works faster, but an external depend).
llvm Pull in dependencies for the sys-devel/llvm codegen backend.
numa Enable NUMA thread balancing policy using sys-process/numactl.
unregisterised Create an unregisterised build in which only the C codegen backend will be available.

gnat-gpl

ada Build the ADA language (GNAT) frontend
bootstrap Used to bootstrap gnat-gpl
cet Enable support for Intel Control Flow Enforcement Technology (CET)
d Enable support for the D programming language
default-stack-clash-protection Build packages with stack clash protection on by default
default-znow Request full relocation on start from ld.so by default
fixed-point Enable fixed-point arithmetic support for MIPS targets in gcc (Warning: significantly increases compile time!)
go Build the GCC Go language frontend.
graphite Add support for the framework for loop optimizations based on a polyhedral intermediate representation
libssp Build SSP support into a dedicated library rather than use the code in the C library (DO NOT ENABLE THIS IF YOU DON'T KNOW WHAT IT DOES)
lto Build using Link Time Optimizations (LTO)
nptl Enable support for Native POSIX Threads Library, the new threading module (requires linux-2.6 or better usually)
objc Build support for the Objective C code language
objc++ Build support for the Objective C++ language
objc-gc Build support for the Objective C code language Garbage Collector
pgo Build GCC using Profile Guided Optimization (PGO)
rust Build support for the Rust language, installs gccrs.
sanitize Build support for various sanitizer functions (ASAN/TSAN/etc...)
ssp Build packages with stack smashing protector on by default
systemtap enable systemtap static probe points
vtv Build support for virtual table verification (a C++ hardening feature)

gnucobol

json Enable support for JSON template formatting via dev-libs/json-c

idris2

chez build using dev-scheme/chez
racket build using dev-scheme/racket
test-full pull in depedndencies to run all tests

inform

tools Install blorbtools for manipulating Blorb files

janet

static-libs install janet static library archive, you must enable this flag for using `jpm build`

jerryscript

debugger Install jerry-debugger

jsonnet

custom-optimization Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS (unsupported)

lazarus

extras Build a lot of extra packages, including lhelp chm viewer program.
gtk2 Use gtk:2 for widgets.
gui Build GUI IDE.
minimal Don't build extra packages from the bigide component

logtalk

fop Support for generating pdf documentation using fop
xslt Support for generating html documentation using xslt

lua

deprecated make deprecated data structures/routines available

luajit

lua52compat Enable some upwards-compatible features from Lua 5.2 that are unlikely to break existing code.

mercury

erlang Support Mercury Erlang grade
trail Support Mercury trail grades

mercury-extras

tommath Enable support for tommath library

mlton

binary install a binary version
bootstrap-smlnj Boostrap mlton with dev-lang/smlnj (takes a long time)
pax-kernel Enable if the user plans to run the package under a pax enabled hardened kernel
stage3 After bootstrap building mlton with dev-lang/smlnj, rebuild mlton with the second stage build of mlton (recommended).

moarvm

asan Enable clang's Address Sanitizer functionality. Expect longer compile time.
clang Use clang compiler instead of GCC
jit Enable Just-In-Time-Compiler. Has no effect except on AMD64 and Darwin.
optimize Enable optimization via CFLAGS
ubsan Enable clang's Undefined Behavior Sanitizer functionality. Expect longer compile time.

mono

pax-kernel Enable if the user plans to run the package under a pax enabled hardened kernel
xen Make mono generate code that is considerably faster on xen VMs but slightly slower on for normal systems.

neko

apache Build Apache modules

nim

experimental Apply experimental patches
test-js Enable tests that require Node.js

nqp

clang Toggle usage of the clang compiler in conjunction with MoarVM
moar Build the MoarVM backend (experimental/broken)

ocaml

flambda Enables the Flambda optimizer: A new intermediate representation (introduced in ocaml 4.03) in the depths of the compiler designed to allow for better inlining.
spacetime Enables the Spacetime memory profiler. See https://caml.inria.fr/pub/docs/manual-ocaml/spacetime.html for more information.

perl

ithreads Enable Perl threads, has some compatibility problems
quadmath Enable 128bit floating point arithmetic via libquadmath

php

apparmor Support FPM application confinement through sys-libs/libapparmor
argon2 Enable password hashing algorithm from app-crypt/argon2
bcmath Enable the BCMath Arbitrary Precision Mathematics extension
cli Enable the Command-Line Interface (CLI) SAPI
coverage Include gcov symbols for test coverage and lcov reports. Only useful for extension developers, and requires GCC.
ctype Enable the Character type checking (ctype) extension
embed Enable embed SAPI
enchant Enable the Enchant spelling library extension using app-text/enchant
ffi Enable the Foreign Function Interface (FFI) extension using dev-libs/libffi
fileinfo Enable the File Information extension
filter Enable the Data Filtering extension
flatfile Add dbm support for flat files
fpm Enable the FastCGI Process Manager SAPI
gd Enable the Image Processing and GD extension (requires media-libs/libjpeg-turbo and media-libs/libpng)
inifile Add dbm support for .ini files
intl Enables the intl extension for extended internalization support
jit Enable PCRE JIT support
ldap-sasl Add SASL support for the PHP LDAP extension using dev-libs/cyrus-sasl
lmdb Enable support for dev-db/lmdb db backend
opcache Enables built-in opcode cache, replacing pecl-apc et al.
pcntl Enable the Process Control extension
pdo Enable the PHP Data Objects extension
phar Enables the phar extension to provide phar archive support
phpdbg Enable the PHP Debug Command Line SAPI (like gdb for php)
session-mm Include dev-libs/mm support for session storage
sharedmem Enable the shmop extension
simplexml Enable the SimpleXML extension
sodium Enable support for crypto through dev-libs/libsodium
sysvipc Enable the PHP System-V semaphore, shared memory and IPC extension
tokenizer Add support for the PHP file parser
tokyocabinet Enable support for dev-db/tokyocabinet db backend
xmlreader Enable the XMLReader extension
xmlwriter Enable the XMLWriter extension
xslt Build the XSL extension

polyml

portable Build the portable interpreter version of Poly/ML instead of native

python

bluetooth Build Bluetooth protocol support in socket module
ensurepip Install the ensurepip module that uses bundled wheels to bootstrap pip and setuptools (if disabled, it will be only possible to use venv `--without-pip`)
libedit Link readline extension against dev-libs/libedit instead of sys-libs/readline
lto Optimize the build using Link Time Optimization (LTO)
pgo Optimize the build using Profile Guided Optimization (PGO) by running Python's test suite and collecting statistics based on its performance. This will take longer to build.
valgrind Disable pymalloc when running under dev-util/valgrind is detected (may incur minor performance penalty even when valgrind is not used)
wininst Install Windows executables required to create an executable installer for MS Windows

python-exec

native-symlinks Install generic symlinks like python and python3. If this flag is disabled, only versioned python3.X executables will be available to end users and ebuilds not using python eclasses.

qu-prolog

pedro Pedro subscription/notification communications system

rakudo

clang Use Clang to compile the MoarVM backend
moar Use the MoarVM as backend

ruby

rdoc Install dev-ruby/rdoc after installing Ruby.
systemtap Enable SystemTAP/DTrace tracing

rust

clippy Install clippy, Rust code linter
dist Install dist tarballs (used for bootstrapping)
lto Optimize the build using Link Time Optimization (LTO)
miri Install miri, an interpreter for Rust's mid-level intermediate representation (requires USE=nightly, sometimes is broken)
nightly Enable nightly (UNSTABLE) features (NOTE: it does not install nightly version, just enables features marked as nightly at time of release)
parallel-compiler Build a multi-threaded rustc (experimental, not tested by upstream)
profiler Build the profiler runtime and rust-demangler tool (needed for '-C profile-generate' or '-C instrument-coverage' codegen opts)
rust-analyzer Install rust-analyzer, A Rust compiler front-end for IDEs (language server)
rust-src Install rust-src, needed by developer tools and for build-std (cross)
rustfmt Install rustfmt, Rust code formatter
system-bootstrap Bootstrap using installed rust compiler
system-llvm Use the system LLVM installation
wasm Build support for the wasm32-unknown-unknown target

rust-bin

clippy Install clippy, Rust code linter
rust-analyzer Install rust-analyzer, A Rust compiler front-end for IDEs (language server)
rust-src Install rust-src, needed by developer tools and for build-std (cross)
rustfmt Install rustfmt, Rust code formatter

scala

binary Install from (Gentoo-compiled) binary instead of building from sources. Set this when you run out of memory during build.

spidermonkey

clang Use Clang compiler instead of GCC
debug Enable assertions to allow for easier debugging of programs that link to spidermonkey -- note this will often crash software on regular end-user systems
lto Enable Link Time Optimization (LTO)

swi-prolog

archive Use libarchive for extension packs
cli Add support for CLI interfaces based on readline and libedit
ipc Add support for TIPC inter-process communication
pgo Optimize the build using Profile Guided Optimization (PGO)
yaml Use libyaml for YAML pack

swig

ccache build ccache-swig(a fast compiler cache)

vala

valadoc Installs valadoc documentation generation tool

xsb

mariadb Enable support for the mariadb database backend

yap

R Enable support for connecting R to Prolog
raptor Enable support for Raptor RDF syntax libarary

zig

llvm Build with LLVM backend and extensions enabled.

dev-libs

aml

examples Build and install examples

antlr-c

debugger Compiles debug info into the library

apache-arrow

compute Build the Arrow Compute Modules
dataset Build the Arrow Dataset Modules
json Enables read/write json format
parquet Enables read/write parquet data format
re2 Build with support for regular expressions using the re2 library

appstream

apt Enables Debians APT support

appstream-glib

fonts Enable fonts support for appstream-builder.
stemmer Add word stemming via dev-libs/snowball-stemmer.

apr

old-kernel Enable compatibility with older kernels
urandom Use /dev/urandom instead of /dev/random

apr-util

nss Install apr_crypto_nss module
openssl Install apr_crypto_openssl module

atcore

gui Build test GUI

bitset

tcmalloc Use tcmalloc from dev-util/google-perftools for allocations

boehm-gc

large optimize for large heap size (also increases max root sets)

boost

context Build and install the Boost.Context (and Boost.Fiber) library and all other Boost libraries that depend on it
debug Build and install only the debug version of the Boost libraries. Only enable this flag if you're developing against boost.
doc Install the full API documentation documentation. This takes over 200MB of extra disk space.
nls Build libboost_locale. This library requires compatible C library interfaces, which might not be provided by uClibc or other embedded libraries.
numpy Optionally build NumPy extensions when Boost.Python is enabled
stacktrace Build the full Boost.Stacktrace dynamic library instead of relying on the header-only implementation
tools Build and install the boost tools (bcp, quickbook, inspect, wave)

botan

boost Use dev-libs/boost
tools Install optional tools for e.g. hashing

check

subunit Enable support for the subunit unit test protocol

crypto++

asm Support assembly hand optimized crypto functions (i.e. faster run time)

cyberjack

tools Build and install optional management tools.

cyrus-sasl

authdaemond Add Courier-IMAP authdaemond unix socket support (net-mail/courier-imap, mail-mta/courier)
ldapdb Enable ldapdb plugin
openldap Add ldap support for saslauthd
sample Enable sample client and server
srp Enable SRP authentication
urandom Use /dev/urandom instead of /dev/random

date

only-c-locale Build only the C locale

dbus-c++

ecore Use Ecore integration
glib Use glib integration

eekboard

libcanberra Enable support for media-libs/libcanberra
xtest Enable support for x11-libs/libXtst

efl

bmp Enable WBMP image loader
dds Enable DDS image loader
drm Enable DRM engine
eet Enable Eet image loader
efl-one Combine multiple core libraries into one libefl.so
fribidi Enable bidirectional text support
glib Enable dev-libs/glib support
harfbuzz Enable complex text shaping and layout support
hyphen Enable text hyphenation support
ibus Enable Intelligent Input Bus
ico Enable Ico image loader
json Enable lottie animation support
mono Enable mono bindings
physics Enable Bullet physics effects and support
pmaps Enable PMAPS image loader
psd Enable PSD image loader
scim Enable Smart Common Input Method
system-lz4 Use system liblz4 instead of bundled one
tga Enable Tga image loader
tgv Enable Tgv image loader
tslib Enable x11-libs/tslib for touchscreen events
unwind Enable debug support via sys-libs/libunwind
xcf Enable XCF image loader
xim Enable X Input Method
xpresent Enable x11-libs/libXpresent support

elfutils

debuginfod Enable debuginfod support, both the debuginfod server and the libdebuginfod client library
lzma Support automatic decompression of LZMA-compressed files and kernel images
utils Install command-line utilities (all the eu-* programs)

fcgi

html Install HTML documentation

folks

telepathy Load contacts from the Telepathy framework
utils Build the folks-inspect utility

fstrm

utils Build fstrm utility programs

gf2x

custom-tune Extra long compile time for tuning hardware specific low-level routines
fft Build an FFT API for multiplication of 2 polynomials over GF(2)

gjs

sysprof Enable profiling data capture support using dev-util/sysprof-capture

glib

dbus Enable dependencies required by glib libraries using dbus service to manage settings saving
elf Enable support for listing and extracting from ELF resource files with gresource tool
mime Pull in shared MIME database that many glib-based applications require at runtime to detect or open files. Warning: do not disable this flag unless installing on a headless server.
sysprof Enable profiling data capture support using dev-util/sysprof-capture
systemtap Build support for profiling and tracing using dev-util/systemtap
utils Install gtester-report utility to generate test report files for your software; build gresource utility with ELF support.

gmime

smime Enable experimental S/MIME support

gmp

asm Enable use of hand optimized assembly routines (faster execution)
cpudetection Enables runtime CPU detection (useful for binpkgs, compatibility on other CPUs). This only works on amd64/x86 at present. If this flag is enabled, GMP will work on a variety of amd64/x86 CPUs and load accelerated routines for use at runtime depending on the CPU in use. This makes it suitable for binary packages (binpkgs). If this flag is disabled, GMP will be tuned for the CPU being used at build-time and may not be usable on other machines.
pic Force static libraries to be built as PIC to avoid TEXTRELs.

gobject-introspection

doctool Install g-ir-doc-tool for generating documentation from introspected data

hidapi

fox Build a x11-libs/fox GUI

imath

large-stack Enables code to take advantage of large stack support

input-pad

eekboard Enable support for dev-libs/eekboard
xtest Enable support for x11-libs/libXtst

intel-compute-runtime

l0 Install the oneAPI Level Zero driver alongside the OpenCL one
vaapi Support the sharing of surfaces with Video Acceleration API (OpenCL Extension #36)

jemalloc

lazy-lock Enable lazy locking (only lock when multi-threaded)
prof Enable allocation profiling
stats Enable statistics calculation/reporting
xmalloc Add support for xmalloc (abort-on-out-of-memory)

json-glib

nls Enable native language support (translations)

kosmindoormap

openinghours Enable support for highlighting currently open amenities/shops/etc.

kreport

marble Enable displaying of maps using kde-apps/marble
scripting Support Qml scripting using dev-qt/qtdeclarative

ktextaddons

designer Build plugins for dev-qt/designer
speech Enable text-to-speech support

libbase58

tools Build command line base58 tool

libbytesize

tools Build bscalc python CLI tool

libcbor

custom-alloc Custom, dynamically defined allocator support

libcdio

minimal Only build the libcdio library and little more, just to be used to link against from multimedia players. With this USE flag enabled, none of the command-line utilities are built, nor is the CDDA library.

libcec

cubox Enable support for enable support for the TDA995x
exynos Enable support for Exynos chipsets
kernel-cec Enable support for Linux kernel CEC framework
raspberry-pi Enable support for the Raspberry Pi
tools Enable build of cec-client and other test and demo executable tools
udev Enable detection of USB-CEC port by udev
xrandr Enable detection of active HDMI using xrandr extensions

libcgroup

daemon Install the configuration tools and init/config files.
tools Install the cgroup rules processing daemon and init/config files.

libclc

spirv Build SPIRV targets

libdbusmenu

gtk Enable support for GTK+2
gtk3 Enable support for GTK+3

libdex

sysprof Enable profiling data capture support using dev-util/sysprof-capture

libdynd

cuda Enable NVIDIA CUDA toolkit support

libevent

clock-gettime Disable use of clock_gettime even if it is available
debug Support for running in debug mode
malloc-replacement Support for replacing the memory management functions
mbedtls Support for net-libs/mbedtls encryption
ssl Support for dev-libs/openssl encryption
verbose-debug Support for verbose debug logging

libffi

exec-static-trampoline Don't rely on dynamic code generation for trampolines.
pax-kernel Use PaX emulated trampolines, for we can't use PROT_EXEC

libffi-compat

pax-kernel Use PaX emulated trampolines, for we can't use PROT_EXEC

libfido2

nfc Enable experimental NFC support

libflatarray

cuda Enables plugins for NVIDIA GPUs (e.g. CUDAAllocator)

libgcrypt

asm Enable assembly for optimization
getentropy Use getentropy function to obtain randomness from the kernel

libgdata

crypt Use app-crypt/gcr for keeping tokens and passwords in non-pageable memory for improved security
gnome-online-accounts Enable net-libs/gnome-online-accounts support

libgit2

gssapi Enable GSSAPI support for SPNEGO auth
ssh Enable SSH transport support
trace Enable tracing support

libgit2-glib

ssh Enable SSH transport support

libgpg-error

common-lisp Install common-lisp files

libgpiod

tools Build some useful gpio tools that use libgpiod.

libical

glib Enable dev-libs/glib interface support

libisoburn

external-filters Allow the use of external processes as file content filters (Note: this is a potential security risk)
external-filters-setuid Also allow the use of external setuid processes as file content filters (Note: this is a potential security risk)
frontend-optional Use dev-tcltk/bwidget which is not strictly required for the frontend
launch-frontend Enable the tcl gui for xorriso
launch-frontend-setuid Enable the tcl gui for xorriso under setuid

libisofs

verbose-debug Enable verbose debug messages

libjcat

gpg Enable GPG verification support via app-crypt/gpgme
pkcs7 Enable PKCS7 verification support via net-libs/gnutls

liblogging

rfc3195 Enables RFC 3195 protocol (aka syslog-reliable) support. If you don't know what this is, you don't need it!
stdlog Enables liblogging's core component (think of it as a the next version of the syslog(3) API).

libmemcached

hsieh Use Hsieh hash algorithm.
libevent Use the libevent event loop interface.
sasl Use sasl auth for communications.

libmemcached-awesome

libevent Use the libevent event loop interface.
sasl Use sasl auth for communications.

libnfc

pcsc-lite Enable NFC drivers that require pcsc-lite

libnl

python Install experimental dev-lang/python bindings
utils Install command line interface utils

liborcus

spreadsheet-model Enable the spreadsheet model implementation
tools Build various low-level parsers

libowfat

diet Compile against dev-libs/dietlibc

libp11

doc Generate and install API documentation for the package.

libpcre

bzip2 Add support for pcregrep command to search within bzip2-compressed files (via app-arch/bzip2).
pcre16 Build PCRE library for 16 bit characters (e.g. UTF-16).
pcre32 Build PCRE library for 32 bit characters (e.g. UTF-32).
readline Add support for command line editing to pcretest, through sys-libs/readline.
zlib Add support for pcregrep command to search within gzip-compressed files (via sys-libs/zlib).

libpcre2

bzip2 Add support for pcregrep command to search within bzip2-compressed files (via app-arch/bzip2).
pcre16 Build PCRE library for 16 bit characters (e.g. UTF-16).
pcre32 Build PCRE library for 32 bit characters (e.g. UTF-32).
readline Add support for command line editing to pcretest, through sys-libs/readline.
zlib Add support for pcregrep command to search within gzip-compressed files (via sys-libs/zlib).

libpeas

glade Install the glade catalog
python Build support for loading dev-lang/python plugins

libpy

sparsehash Include libpy wrappers for dev-cpp/sparsehash

librdkafka

lz4 Enable support for Kafka's LZ4 compression based on KIP-57 (uses app-arch/lz4)

librelp

gnutls Use GnuTLS
openssl Use OpenSSL

libsecp256k1

asm Enable x86_64 assembly optimisation
ecdh Enable ECDH shared secret computation
ellswift Enable ElligatorSwift encoding for public keys
endomorphism Enable endomorphism
experimental Allow experimental USE flags
extrakeys Enable extrakeys module
lowmem Reduce runtime memory usage at the expense of performance (ecmult window size 4, gen precision 2)
recovery Enable ECDSA pubkey recovery module
schnorr Enable Schnorr signature module
test-openssl Enable OpenSSL comparison tests

libslz

tools Install additional tools (zenc, zdec)

libsodium

asm Enables assembly implementations
urandom Use /dev/urandom instead of /dev/random

libtermkey

demos Install demos, which pulls in dev-libs/glib

libtomcrypt

libtommath Uses dev-libs/libtommath for mathematical operations
tomsfastmath Uses dev-libs/tomsfastmath for mathematical operations

libucl

regex Enable regex support
sign Enable signatures check
urls Enable URLs fetch
utils Install utils for checking other configs

libunibreak

doc Install html API documentation.

libverto

glib Support event loops using dev-libs/glib
libev Support event loops using dev-libs/libev
libevent Support event loops using dev-libs/libevent
tevent Support event loops using sys-libs/tevent

libvoikko

expvfst Enable experimental features of VFST morphology backend
hfst Enable HFST morphology backend

libxlsxwriter

openssl Use dev-libs/openssl for MD5 digest

libxmlb

stemmer Enable language stemming support

libzia

ftdi Enable support for FTDI USB chips

libzip

mbedtls Use net-libs/mbedtls as TLS provider
tools Install binary tools to compare, modify and merge zip files
aspell Adds support for app-text/aspell spell checker
hunspell Adds support for app-text/hunspell spell checker

log4cplus

explicit-initialization Require explicit initialization
iconv Use inconv for wchar_t <-> char conversions. See also log4cplus's unicode.txt documentation
server Build the logging server

log4cxx

smtp Offer SMTP support via net-libs/libesmtp

m17n-lib

X Build the Graphical User Interface API and utilities
anthy Enable support for app-i18n/anthy input method
athena Enable the MIT Athena widget set (x11-libs/libXaw)
gd Build API and utilities based on media-libs/gd. This flag is only meaningful if the X USE flag is also enabled
libotf Use dev-libs/libotf to handle OpenType fonts
libxml2 Use dev-libs/libxml2 to parse XML

mimalloc

hardened Enable exploit mitigations

modsecurity

fuzzyhash Support fuzzy hash computations (to detect malware, for example) using the app-crypt/ssdeep package.
geoip2 Pull in dev-libs/libmaxminddb for use by the SecGeoLookupDb directive.
json Suppose JSON in the request body parser through dev-libs/yajl.
lmdb Add LMDB backend support
pcre2 Use dev-libs/libpcre2 as regex implementation

ncnn

tools Enable installation of various tools in addition to the library

nettle

asm Support assembly hand optimized crypto functions (i.e. faster run time)

nss

cacert Include root/class3 certs from CAcert (https://www.cacert.org/)
utils Compile and install all extra binaries, such as certutil, modutil and few more

onigmo

combination-explosion-check enable combination explosion check
crnl-as-line-terminator enable CR+NL as line terminator

oniguruma

crnl-as-line-terminator Enable CR+NL as line terminator

opencryptoki

tpm Enable support for Trusted Platform Module (TPM) using app-crypt/trousers

openct

debug Add debug output to the driver library for pcsc-lite.
pcsc-lite Build a driver library for sys-apps/pcsc-lite, providing PC/SC API access to devices supported by OpenCT.

openobex

irda Enable IrDA support

opensc

ctapi Use CT-API for accessing Smartcard hardware
notify Enable notifications
openct Use dev-libs/openct (and CT-API) for accessing Smartcard hardware
pace Use dev-libs/openpace for EAC version 2 support
pcsc-lite Use sys-apps/pcsc-lite (and PC/SC API) for accessing Smartcard hardware
secure-messaging Enable secure messaging

openssl

asm Support assembly hand optimized crypto functions (i.e. faster run time)
bindist Disable/Restrict EC algorithms (as they seem to be patented) -- note: changes the ABI
fips Enable FIPS provider
ktls Enable support for Kernel implementation of TLS (kTLS)
rfc3779 Enable support for RFC 3779 (X.509 Extensions for IP Addresses and AS Identifiers)
sslv2 Support for the old/insecure SSLv2 protocol -- note: not required for TLS/https
sslv3 Support for the old/insecure SSLv3 protocol -- note: not required for TLS/https
tls-compression Enable support for discouraged TLS compression
tls-heartbeat Enable the Heartbeat Extension in TLS and DTLS
weak-ssl-ciphers Build support for SSL/TLS ciphers that are considered "weak"

openssl-compat

asm Support assembly hand optimized crypto functions (i.e. faster run time)
bindist Disable/Restrict EC algorithms (as they seem to be patented) -- note: changes the ABI
rfc3779 Enable support for RFC 3779 (X.509 Extensions for IP Addresses and AS Identifiers)
sslv2 Support for the old/insecure SSLv2 protocol -- note: not required for TLS/https
sslv3 Support for the old/insecure SSLv3 protocol -- note: not required for TLS/https
tls-compression Enable support for discouraged TLS compression
tls-heartbeat Enable the Heartbeat Extension in TLS and DTLS
weak-ssl-ciphers Build support for SSL/TLS ciphers that are considered "weak"

optix

headers-only Download and install only the header files

pkcs11-helper

nss Enable NSS crypto engine

pocl

accel Enable the generic hardware accelerator device driver
conformance Ensures that certain build options which would result in non-conformant pocl build stay disabled. Note that this does not quarantee a fully conformant build of pocl.
cuda Enable the CUDA backend for NVIDIA GPUs
float-conversion When enabled, OpenCL printf() call's f/e/g formatters are handled by pocl. When disabled, these are handled by system C library.
hardening Enable hardening against various attacks. May worsen performance
hwloc Enable hwloc support
lto Adds support for link time optimization
memmanager Enables custom memory manager. Except for special circumstances, this should be disabled

poco

7z Add Support for the 7z archive format
activerecord Add ActiveRecord support
cppparser Build and install a minimal C++ parser
crypto Encryption and digital signing classes
data Database abstraction layer to easily send/retrieve data to/from various databases
file2pagecompiler Utility to convert ordinary files to Page Compiler source files
json Add JSON support
jwt Add JSON Web Token support
mariadb Prefer dev-db/mariadb-connector-c over dev-db/mysql-connector-c
mongodb Add dev-db/mongodb support
net Classes to write network clients & servers
pagecompiler Simple compiler translating HTML pages containing embedded C++ code into HTTPRequestHandler classes
pocodoc POCO documentation generator
prometheus Add prometheus monitoring system support
util Several utility classes (like logger, timer, config file parser)
zip Add support for the zip & gz archive formats

ppl

cdd Build the ppl_lcdd program for vertex/facet enumeration accepting the same input format as the programs shipped with sci-libs/cddlib and sci-libs/lrslib
lpsol Build the ppl_lpsol linear program solver that uses sci-mathematics/glpk for its input routines

qcoro5

network Build dev-qt/qtnetwork support
qml Enable QML/QtQuick support via dev-qt/qtdeclarative
testlib Install coroutine-friendly versions of dev-qt/qttest macros
websockets Build dev-qt/qtwebsockets support

qhotkey

qt6 Use Qt6 dependencies

quazip

qt5 Build with Qt5 support
qt6 Build with Qt6 support

raft

zfs ZFS support

rocksdb

numa Enable NUMA support
tbb Enable support for dev-cpp/tbb

sentry-native

breakpad Use dev-util/breakpad as the crash handler
curl Enable support for automated uploading of crash reports

serd

tools Build command line utilities

serdisplib

tools Build optional tools.

sexpp

cli Build sexp console application

simdjson

all-impls Enable all implementations rather than only onem
tools Build and install extra command line tools

softhsm

gost Enable gost algorithm
migration-tool Build db migration tool

sord

tools Build command line utilities

starpu

cuda Enable NVIDIA CUDA toolkit support
gcc-plugin Enable GCC extension plugin (experimental)
opencl Enable OpenCL support
spinlock-check Enable spinlock check

thrift

libevent Build support for dev-libs/libevent

tinyxml

stl Compile with TIXML_USE_STL support

tntnet

server Enable tntnet server daemon

totem-pl-parser

archive Enables ISO detection with app-arch/libarchive
crypt Support AmazonAMZ decoding with dev-libs/libgcrypt
uchardet Enable charset discovery via app-i18n/uchardet

tre

agrep Build agrep tool
alloca Enable if you want TRE to use alloca() instead of malloc() when allocating memory needed for regexec operations
approx Enable the approximate matching functionality

uriparser

unicode Add support for functions working with character type wchar_t (e.g. uriParseSingleUriW with trailing "W") which increases compile time and resulting binary file size by roughly factor 2.

weston

desktop Enable the desktop shell
drm Enable drm compositor support
editor Install wayland-editor example application
fullscreen Enable fullscreen shell
gles2 Use GLESv2 cairo instead of full GL
headless Headless backend and a noop renderer, mainly for testing purposes
ivi Enable the IVI shell
kiosk Enable the kiosk shell
pipewire Enable virtual remote output with Pipewire on DRM backend
rdp Enable Remote Desktop Protocol compositor support
remoting Enable plugin to stream output to remote hosts using media-libs/gstreamer
resize-optimization Increase performance, allocate more RAM. Recommended to disable on Raspberry Pi
screen-sharing Enable screen-sharing through RDP
seatd Enable support for rootless session via sys-auth/seatd
wayland-compositor Enable Wayland compositor support
xwayland Enable ability support native X11 applications

xapian

inmemory Enabled inmemory backend db support
remote Enabled remote backend db support

xerces-c

iconv Use iconv (virtual/libiconv) as message loader and transcoder (in general it would be possible to use iconv only as message loader and something else like icu or the native method as transcoder and vice-versa, but this is a less common case and hard to handle)
threads Enable threading support through pthread (or other libraries on AIX, IRIX, HPUX, Solars). Highly recommended

xmlrpc-c

abyss Build the Abyss mini web-server.
libxml2 Use dev-libs/libxml2 to parse XML instead of the internal expat library.
threads Controls whether to build the Abyss web-server with pthreads or fork 'threading'.

xmlsec

gcrypt Install xmlsec-gcrypt library
gnutls Install xmlsec-gnutls library
http Allow fetching over HTTP via libxml2.
nss Install xmlsec-nss library
openssl Install xmlsec-openssl library

yaz

ziffy Install ziffy, a promiscuous Z39.50 APDU sniffer

dev-lisp

clisp

hyperspec Use local hyperspec instead of online version
svm Build CLISP with support for the Support Vector Machine module

clx

doc Builds documentation

cmucl

X Build CLX, CLM, or Hemlock
doc Installs package documentation
source Include source code for CMUCL in installation

ecl

gengc Use generational garbage collection (experimental)
precisegc Use type information during garbage collection (experimental)

gcl

ansi Build a GCL with ANSI support (else build a traditional CLtL1 image)
athena Build xgcl - an interface to x11-libs/libXaw

sbcl

system-bootstrap Bootstrap SBCL using either system SBCL installation or dev-lisp/clisp

dev-lua

lua-cjson

internal-fpconv Enable internal number conversion routines, can increase overall performance by up to 50%

dev-ml

lablgtk

glade Enable gnome-base/libglade bindings compilation
gnomecanvas Enable gnome-base/libgnomecanvas bindings compilation
sourceview Enable GtkSourceView (x11-libs/gtksourceview) support

logs

cli Enables the Logs_cli library that provides command line support for controlling Logs.
fmt Enables the Logs_fmt reporter.
lwt Enables the Logs_lwt library that provides Lwt logging functions.

ocaml-fileutils

ocamlopt Whether the OCaml native code compiler is used. Must be set globally and match dev-lang/ocaml.

ocaml-gettext

ocamlopt Whether the OCaml native code compiler is used. Must be set globally and match dev-lang/ocaml.

ocaml-gettext-camomile

ocamlopt Whether the OCaml native code compiler is used. Must be set globally and match dev-lang/ocaml.

ocaml-gettext-stub

ocamlopt Whether the OCaml native code compiler is used. Must be set globally and match dev-lang/ocaml.

ocamlnet

httpd Enables net-httpd web server component
zip Enables netzip support to read/write gzip data using object channels

stdlib-shims

ocamlopt Whether the OCaml native code compiler is used. Must be set globally and match dev-lang/ocaml.

tiny_httpd

camlzip Interface to camlzip for tiny_httpd

uutf

utftrip Builds and install the utftrip executable: Among other things, reads unicode on stdin and rewrites it on stdout.

zarith

mpir Use MPIR library instead of GMP.

dev-perl

App-Nopaste

browser Spawn browser with pasted page
clipboard copying of URLs with -x/--copy
gitlab Ensure git is installed for reading/passing GitLab authentication
pastebin pastebin.com support

Boulder

genbank Provide support with Boulder::Genbank for decoding Genbank data records
store Provide support with Boulder::Store for persisting Stone objects

Business-ISBN

barcode Install dev-perl/GD-Barcode for rendering ISBN numbers as barcodes

Config-Any

conf Install dev-perl/Config-General to support decoding .conf/.cnf files
ini Install dev-perl/Config-Tiny to support decoding INI config files
json Install support libraries to support decoding JSON config files
xml Install support libraries to support decoding XML config files
yaml Install support libraries to support decoding YAML config files

Cookie-Baker

xs Install dev-perl/Cookie-Baker-XS for accelerated performance

Coro

ev Build support for using dev-perl/EV as an event-loop via Coro::EV
event Build support for using dev-perl/Event as an event-loop via Coro::Event

DBD-MariaDB

mariadb Use dev-db/mariadb-connector-c as the client library
mysql Use dev-db/mysql-connector-c as the client library

DBD-SQLite

system-sqlite Use the system-wide dev-db/sqlite installation

DBD-mysql

mariadb Use dev-db/mariadb-connector-c as the client library
mysql Use dev-db/mysql-connector-c as the client library
ssl Compile in support for SSL connections via libmysqlclient

DBIx-Class

admin Modules required for the DBIx::Class administrative library
admin-script Modules required for the CLI DBIx::Class interface dbicadmin
deploy Modules required for "deploy" in DBIx::Class::Storage::DBI and "deploymen_statements" in DBIx::Class::Storage::DBI
replicated Modules required for DBIx::Class::Storage::DBI::Replicated

File-HomeDir

xdg Ensure XDG Semantics for returned paths via x11-misc/xdg-user-dirs

File-Which

pwhich Install dev-perl/App-pwhich which used to be a part of this package

GD

animgif Enable animated gif support
fcgi Build for FastCGI compatibility via dev-libs/fcgi instead of using PerlIO

HTML-Mason

modperl Enable www-apache/mod_perl support

HTTP-Entity-Parser

xs Install C-Based dependieces for faster performance

JSON

xs Install C-based dev-perl/JSON-XS for faster performance

JSON-MaybeXS

xs Install a C-Based backend to make JSON encode/decode fast

List-MoreUtils

xs Install C-Based backend implementation for performance

MCE

sereal Install dev-perl/Sereal-Encoder and decoder for faster worker IPC

Mail-IMAPClient

md5 Install support for DIGEST-MD5 and CRAM-MD5 Authentication
ntlm Install support for NTLM Authentication
ssl Install support for SSL Connections
zlib Install support for COMPRESS DEFLATE connections

Net-SSH2

gcrypt Use libgcrypt instead of openssl

PDL

badval Enable bad values support
hdf Enable HDF (version 4) format support
netpbm Enable NETPBM and MPEG support
pdl2 Build pdf2 shell (requires Devel-REPL)
pgplot Enable PGPLOT plotting capabilities

Ref-Util

xs Install C-Based dev-perl/Ref-Util-XS for accelerated performance

Sub-Name

suggested Install extra dependencies needed for extended regression tests

Sysadm-Install

hammer Enable hammer() funtion to run a command in the shell and simulate a user hammering the ENTER key to accept defaults on prompts

Test-Warnings

suggested Install optional dependencies for extra tests

Text-CSV

xs Install dev-perl/Text-CSV_XS for accelerated decoding

WWW-Form-UrlEncoded

xs Install C-Based dependieces for faster performance

perl-headers

debug Add source locations in generated .ph files to assist with debugging when errors occur
sizeof-warning Include logic to warn when a .ph file tries to use a sizeof() that is unknown

dev-php

PEAR-HTTP_Request2

curl Force dev-lang/php to be compiled with curl extension
fileinfo Force dev-lang/php to be compiled with fileinfo extension
ssl Force dev-lang/php to be compiled with ssl extension
zlib Force dev-lang/php to be compiled with zlib extension

PEAR-PHP_Beautifier

cli Require dev-lang/php to be built with the "cli" SAPI and install the php_beautifier script.

maxmind-db-reader

extension Build the C extension that uses dev-libs/libmaxminddb

pecl-apcu

lock-pthreadmutex Enable pthread mutex locking
lock-pthreadrw Enable pthread read/write locking
lock-semaphore Enable semaphore locks instead of fcntl
lock-spinlock Enable spin locks (EXPERIMENTAL)

pecl-event

extra Add support of the Libevent extra API

pecl-memcached

igbinary Enable support for the igbinary serializer
json Enable support for json serialization

pecl-redis

igbinary Enables igbinary serialisation support
json Enables json serializer support

swoole

http2 Add support for HTTP/2 protocol via net-libs/nghttp2

dev-python

PyQt5

bluetooth Build bindings for the QtBluetooth module
dbus Build bindings for the QtDBus module
declarative Build bindings for the QtQml and QtQuick modules and enable the qmlscene plugin
designer Build bindings for the QtDesigner module and enable the designer plugin
gui Build bindings for the QtGui module
help Build bindings for the QtHelp module
location Build bindings for the QtLocation module
multimedia Build bindings for the QtMultimedia module
network Build bindings for the QtNetwork module
opengl Build bindings for the QtOpenGL module
positioning Build bindings for the QtPositioning module
printsupport Build bindings for the QtPrintSupport module
sensors Build bindings for the QtSensors module
serialport Build bindings for the QtSerialPort module
speech Build bindings for the QtTextToSpeech module
sql Build bindings for the QtSql module
svg Build bindings for the QtSvg module
testlib Build bindings for the QtTest module
webchannel Build bindings for the QtWebChannel module
websockets Build bindings for the QtWebSockets module
widgets Build bindings for the QtWidgets module
x11extras Build bindings for the QtX11Extras module
xmlpatterns Build bindings for the QtXmlPatterns module

PyQt6

bluetooth Build bindings for the QtBluetooth module
dbus Build bindings for the QtDBus module
designer Build bindings for the QtDesigner module and enable the designer plugin
gui Build bindings for the QtGui module
help Build bindings for the QtHelp module
multimedia Build bindings for the QtMultimedia module
network Build bindings for the QtNetwork module
nfc Build bindings for the QtNfc module
opengl Build bindings for the QtOpenGL module
pdfium Build bindings for the QtPdf module (uses pdfium from dev-qt/qtwebengine)
positioning Build bindings for the QtPositioning module
printsupport Build bindings for the QtPrintSupport module
qml Build bindings for the QtQml module and enable the qml plugin
quick Build bindings for the QtQuick module
quick3d Build bindings for the QtQuick3D module
sensors Build bindings for the QtSensors module
serialport Build bindings for the QtSerialPort module
spatialaudio Build bindings for the QtSpatialAudio module
speech Build bindings for the QtTextToSpeech module
sql Build bindings for the QtSql module
svg Build bindings for the QtSvg module
testlib Build bindings for the QtTest module
webchannel Build bindings for the QtWebChannel module
websockets Build bindings for the QtWebSockets module
widgets Build bindings for the QtWidgets module
xml Build bindings for the QtXml module

PyQt6-WebEngine

quick Build bindings for the QtWebEngineQuick module
widgets Build bindings for the QtWebEngineWidgets module

QtPy

designer Pull in bindings for the QtDesigner module and enable the designer plugin
gui Pull in bindings for the QtGui module
help Pull in bindings for the QtHelp module
multimedia Pull in QtMultimedia and QtMultimediaWidgets modules
network Pull in bindings for the QtNetwork module
opengl Pull in bindings for the QtOpenGL module
positioning Pull in bindings for the QtPositioning module
printsupport Pull in bindings for the QtPrintSupport module
pyqt5 Use dev-python/PyQt5 as Qt for Python implementation
pyqt6 Use dev-python/PyQt6 as Qt for Python implementation
pyside2 Use dev-python/pyside2 as Qt for Python implementation
pyside6 Use dev-python/pyside6 as Qt for Python implementation
qml Build bindings for the QtQml
quick Build bindings for the QtQuick
sensors Pull in bindings for the QtSensors module
serialport Pull in bindings for the QtSerialPort module
speech Pull in bindings for the QtTextToSpeech module
sql Pull in bindings for the QtSql module
svg Pull in bindings for the QtSvg module
testlib Pull in bindings for the QtTest module
webchannel Pull in bindings for the QtWebChannel module
webengine Pull in QtWebEngine and QtWebEngineWidgets modules
websockets Pull in bindings for the QtWebSockets module
widgets Pull in bindings for the QtWidgets module
xml Pull in QtXml module

amqp

extras Install extra tools to generate initial Python mod from an AMQP XML file

autobahn

xbr Add support for XBR decentralized data markets and etherium blockchain

bpython

clipboard Enable copying to clipboard using dev-python/pyperclip
jedi Enable autocompletion using dev-python/jedi
watch Enable watching paths using dev-python/watchdog

cbor2

native-extensions Compiles native "C" extensions (speedups, instead of using python fallback code).

cvxopt

dsdp Use interior point library sci-libs/dsdp
glpk Use GNU Linear Programming Kit sci-mathematics/glpk

dnspython

dnssec Use dev-python/cryptography to enable low-level DNSSEC RSA, DSA, ECDSA and EdDSA signature validation.

editorconfig-core-py

cli Install command line interface as well as python library

fritzconnection

qrcode Install dependencies needed to generate QR Codes for WiFi login.

frozenlist

native-extensions Compile native C extensions (speedups, instead of using Python fallback code).

httpx

cli Install the CLI "httpx" client.

hypothesis

cli Install a CLI tool used to write tests.

icalendar

doc Generate examples and other extra documentation

immutables

native-extensions Compiles native "C" extensions (speedups, instead of using Python fallback code).

ipython

nbconvert Enable support for converting notebooks to various formats using app-text/pandoc
notebook Install requirements for the web notebook based on dev-python/tornado

markdown-exec

ansi Enable support for rendering ANSI colours in HTML code blocks

matplotlib

excel Pull dev-python/xlwt for the exceltools toolkit
gtk3 Enable x11-libs/gtk+:3 support
webagg Enable webagg backend that uses dev-python/tornado

mido

portmidi Support using media-libs/portmidi as MIDI back-end
rtmidi Support using media-libs/rtmidi as MIDI back-end

mkdocs-material

social Install the dependencies of the "social" plugin.

msgpack

native-extensions Compiles native "C" extensions (speedups, instead of using python fallback code).

multidict

native-extensions Compile native C extensions (speedups, instead of using Python fallback code).

mypy

native-extensions Compiles native C extensions (speedups, instead of using Python fallback code).

pandas

full-support Pull all packages to give pandas full support

paramiko

server Enable server feature

peewee

native-extensions Compiles native C extension for more complete SQLite3 support.

pillow

imagequant Build with Image Quantization Library support

pivy

quarter Use media-libs/quarter for GUI bindings
soqt Use media-libs/SoQt for GUI bindings

pyarrow

parquet Enables read/write parquet data format

pydantic

native-extensions Compiles native "C" extensions.

pyglet

image Enable support for image formats other than PNG and BMP

pymongo

native-extensions Compiles native C extensions
test-full Run test suite in full, including tests that run a local database instance.

pyocr

cuneiform Enable support for the app-text/cuneiform OCR engine
tesseract Enable support for the app-text/tesseract OCR engine

pypax

ptpax Enable PT_PAX_FLAGS support.
xtpax Enable XATTR_PAX_FLAGS support.

pypy

full-stdlib Install complete stdlib as necessary to use PyPy for general purpose programs. By default, only a limited subset that is used when building dev-python/pypy3-exe is installed. Note that PyPy2.7's stdlib contains multiple known vulnerabilities.

pypy-exe

low-memory Build using PyPy with the engine configured towards low memory footprint. This makes it possible to build PyPy using ~3.5G of RAM on amd64 and ~half of that on x86, at the cost of lengthened build time.

pypy3-exe

low-memory Build using PyPy with the engine configured towards low memory footprint. This makes it possible to build PyPy using ~3.5G of RAM on amd64 and ~half of that on x86, at the cost of lengthened build time.

pypy3_10

ensurepip Install the ensurepip module that uses bundled wheels to bootstrap pip and setuptools (if disabled, it will be only possible to use venv `--without-pip`)

pypy3_10-exe

low-memory Build using PyPy with the engine configured towards low memory footprint. This makes it possible to build PyPy using ~3.5G of RAM on amd64 and ~half of that on x86, at the cost of lengthened build time.

pypy3_9

ensurepip Install the ensurepip module that uses bundled wheels to bootstrap pip and setuptools (if disabled, it will be only possible to use venv `--without-pip`)

pypy3_9-exe

low-memory Build using PyPy with the engine configured towards low memory footprint. This makes it possible to build PyPy using ~3.5G of RAM on amd64 and ~half of that on x86, at the cost of lengthened build time.

pyrsistent

native-extensions Compiles native C extensions (speedups, instead of using python fallback code).

pyside2

3d Build Qt3DCore, Qt3DAnimation, Qt3DExtras, Qt3DInput, Qt3DLogic, and Qt3DRender modules
charts Build QtCharts module
concurrent Build QtConcurrent module
datavis Build QtDataVisualization module
designer Build QtDesigner and QtUiTools modules
gles2-only Build QtGui "QOpenGL*" classes
gui Build QtGui module
help Build QtHelp module
location Build QtLocation module
multimedia Build QtMultimedia and QtMultimediaWidgets modules
network Build QtNetwork module
positioning Build QtPositioning module
printsupport Build QtPrintSupport module
qml Build QtQml module
quick Build QtQuick and QtQuickWidgets modules
scxml Build QtScxml module
sensors Build QtSensors module
speech Build QtTextToSpeech module
sql Build QtSql module
svg Build QtSvg module
testlib Build QtTest module
webchannel Build QtWebChannel module
webengine Build QtWebEngine and QtWebEngineWidgets modules
websockets Build QtWebSockets module
widgets Build QtWidgets module
x11extras Build QtX11Extras module
xml Build QtXml module
xmlpatterns Build QtXmlPatterns module

pyside6

3d Build Qt3DCore, Qt3DAnimation, Qt3DExtras, Qt3DInput, Qt3DLogic, and Qt3DRender modules
bluetooth Build QtBluetooth module
charts Build QtCharts module
concurrent Build QtConcurrent module
designer Build QtDesigner and QtUiTools modules
gles2-only Build QtGui "QOpenGL*" classes
gui Build QtGui module
help Build QtHelp module
location Build QtLocation module
multimedia Build QtMultimedia and QtMultimediaWidgets modules
network Build QtNetwork module
network-auth Build QtNetworkAuth module
nfc Build QtNfc module
pdfium Build QtPdf module
positioning Build QtPositioning module
printsupport Build QtPrintSupport module
qml Build QtQml module
quick Build QtQuick and QtQuickWidgets modules
quick3d Build QtQuick3D and QtQuickWidgets modules
scxml Build QtScxml module
sensors Build QtSensors module
serialport Build QtSerialPort modules
spatialaudio Build QtSpatialAudio module
speech Build QtTextToSpeech module
sql Build QtSql module
svg Build QtSvg module
testlib Build QtTest module
webchannel Build QtWebChannel module
webengine Build QtWebEngine and QtWebEngineWidgets modules
websockets Build QtWebSockets module
widgets Build QtWidgets module
xml Build QtXml module

python-box

native-extensions Compiles native C extensions

python-lsp-server

all-plugins Pull in all optional plugins

python-mpd2

twisted Enable twisted support

python-stdnum

vies Enable VIES

pyudev

qt5 Install PyQt5 bindings

pyzmq

drafts Enable draft API support

qiskit-terra

visualization Enable visualization modules

rarfile

compressed Enables the module to support compressed v3 archives by calling the app-arch/unrar.

reedsolo

native-extensions Compile native C extensions.

rfc3986

idna enable support for the IDNA specification (RFC 5891)

rpyc

gdb Run tests depending on sys-devel/gdb
numpy Run tests depending on dev-python/numpy, dev-python/pandas

shiboken2

docstrings Expose documentation as Python docstrings (recommended)
numpy Implicitly convert passed NumPy arrays to Qt lists
vulkan Generate "QSurface::VulkanSurface" bindings

shiboken6

docstrings Expose documentation as Python docstrings (recommended)
numpy Implicitly convert passed NumPy arrays to Qt lists
vulkan Generate "QSurface::VulkanSurface" bindings

simplejson

native-extensions Compiles native "C" extensions (speedups, instead of using Python fallback code).

subprocess-tee

test-full Enable full test mode. Pulls in many additional dependencies, and requires having been emerged without this flag first in order to avoid a circular dependency.

sympy

aesara Add support for dev-python/aesara
imaging Add support for dev-python/pillow
ipython Add support for dev-python/ipython
mathml Add support for mathml
pyglet Use dev-python/pyglet for plots and print preview
symengine Add support for a dev-python/symengine backend
texmacs Add app-office/texmacs interface

tables

cpudetection Enables runtime CPU detection (useful for bindist, compatibility on other CPUs)

tpm2-pytss

fapi Enable feature API (requires tpm2-tss be compile with thes same)

translate-toolkit

html Support conversion between po and html files
ical Support conversion between po and ical files
ini Support conversion between po and ini files
subtitles Support conversion between po and sub files
yaml Support YAML format

twisted

conch include Twisted SSHv2 implementation
http2 include http2 support
serial include serial port support

websockets

native-extensions Compiles native C extensions

wrapt

native-extensions Compiles native C extensions (speedups, instead of using python fallback code).

zeep

async Add async support

dev-qt

designer

declarative Build the qdeclarativeview plugin

linguist-tools

qml Enable QML support in lupdate

qdoc

qml Enable QML/JS parsing support

qt-creator

clang Build clang-based plugins for C/C++ development (code model, formatting, static analysis)
designer Enable designer for QtWidgets-based UIs
help Enable the integrated dev-qt/qt-docs viewer (also needed for examples)
qmldesigner Build QmlDesigner and related plugins (Insight, StudioWelcome)
serialterminal Build the serial terminal plugin
tracing Build plugins requiring tracing capabilities (CtfVisualizer, PerfProfiler, QmlProfiler)
webengine Use dev-qt/qtwebengine with the help USE rather than bundled litehtml

qt-docs

3d Install documentation for dev-qt/qt3d
activeqt Install documentation for ActiveQt (unpackaged, Windows-only)
assistant Install documentation for dev-qt/assistant
bluetooth Install documentation for dev-qt/qtbluetooth
charts Install documentation for dev-qt/qtcharts
concurrent Install documentation for dev-qt/qtconcurrent
connectivity Install documentation for dev-qt/qtconnectivity
datavis Install documentation for dev-qt/qtdatavis3d (unpackaged for Qt6)
declarative Install documentation for dev-qt/qtdeclarative
designer Install documentation for dev-qt/designer
gamepad Install documentation for dev-qt/qtgamepad (available in qt overlay only)
graphicaleffects Install documentation for dev-qt/qtgraphicaleffects
graphs Install documentation for QtGraphs (unpackaged)
grpc Install documentation for QtGRPC (unpackaged)
gui Install documentation for dev-qt/qtgui
help Install documentation for dev-qt/qthelp
html Install documentation in HTML format
httpserver Install documentation for QtHTTPServer (unpackaged)
imageformats Install documentation for dev-qt/qtimageformats
linguist Install documentation for dev-qt/linguist
location Install documentation for dev-qt/qtlocation
lottie Install documentation for QtLottie (unpackaged)
multimedia Install documentation for dev-qt/qtmultimedia
network Install documentation for dev-qt/qtnetwork
networkauth Install documentation for dev-qt/qtnetworkauth
positioning Install documentation for dev-qt/qtpositioning
printsupport Install documentation for dev-qt/qtprintsupport
qch Install documentation in QCH format
qdoc Install documentation for dev-qt/qdoc
qt5compat Install documentation for dev-qt/qt5compat
quick3d Install documentation for dev-qt/qtquick3d
quick3dphysics Install documentation for QtQuick3DPhysics (unpackaged)
quickcontrols Install documentation for dev-qt/qtquickcontrols
quickcontrols2 Install documentation for dev-qt/qtquickcontrols2
quickeffectmaker Install documentation for QtQuickEffectMaker (unpackaged)
remoteobjects Install documentation for QtRemoteObjects (unpackaged)
script Install documentation for dev-qt/qtscript
scxml Install documentation for dev-qt/qtscxml
sensors Install documentation for dev-qt/qtsensors
serialbus Install documentation for dev-qt/qtserialbus (unpacakged for Qt6)
serialport Install documentation for dev-qt/qtserialport
shadertools Install documentation for dev-qt/qtshadertools
speech Install documentation for dev-qt/qtspeech
sql Install documentation for dev-qt/qtsql
svg Install documentation for dev-qt/qtsvg
timeline Install documentation for dev-qt/qtquicktimeline
tools Install documentation for dev-qt/qttools
virtualkeyboard Install documentation for dev-qt/qtvirtualkeyboard
wayland Install documentation for dev-qt/qtwayland
webchannel Install documentation for dev-qt/qtwebchannel
webengine Install documentation for dev-qt/qtwebengine
websockets Install documentation for dev-qt/qtwebsockets
webview Install documentation for dev-qt/qtwebview (unpackaged for Qt6)
widgets Install documentation for dev-qt/qtwidgets
x11extras Install documentation for dev-qt/qtx11extras
xmlpatterns Install documentation for dev-qt/qtxmlpatterns

qt3d

gamepad Add support for gamepad hardware via dev-qt/qtgamepad
qml Build QML/QtQuick bindings

qt5compat

qml Build QML/QtQuick bindings and imports

qtbase

X Build the XCB platform plugin and enable X11 integration
concurrent Build Qt6Concurrent module
dbus Build Qt6DBus module
eglfs Build the EGL Full Screen/Single Surface platform plugin
evdev Enable support for input devices via evdev
gssapi Enable support for GSSAPI (virtual/krb5)
gtk Build the GTK platform theme plugin
gui Build Qt6Gui module
libinput Enable support for input devices via dev-libs/libinput
libproxy Use net-libs/libproxy for automatic HTTP/SOCKS proxy configuration
network Build Qt6Network module
renderdoc Enable support for capturing graphic's API calls using media-gfx/renderdoc
sql Build Qt6Sql module
tslib Enable support for touchscreen devices via x11-libs/tslib
widgets Build Qt6Widgets module

qtbluetooth

qml Build QML/QtQuick bindings and imports

qtcharts

qml Build QML/QtQuick bindings and imports

qtconnectivity

nfc Enable support for the Near Field Communication protocol

qtcore

old-kernel Disable syscalls not available on Linux kernels older than 4.11

qtdatavis3d

qml Build QML/QtQuick bindings and imports

qtdeclarative

localstorage Build the LocalStorage import for QtQuick (requires QtSql)
opengl Enable OpenGL support
sql Enable QtSQL support
widgets Enable QtWidgets support

qtdiag

network Report network information
widgets Report widget style information

qtgamepad

evdev Enable support for input devices via evdev
qml Build QML bindings

qtgui

X Build the XCB platform plugin and enable X11 integration
egl Enable EGL integration
eglfs Build the EGL Full Screen/Single Surface platform plugin
evdev Enable support for input devices via evdev
ibus Build the IBus input method plugin
libinput Enable support for input devices via dev-libs/libinput
linuxfb Enable Linux framebuffer support for embedded devices
tslib Enable support for touchscreen devices via x11-libs/tslib
tuio Build plugin to receive touch events over the TUIO protocol
wayland Provide dev-qt/qtwayland to ensure Qt applications can be run as Wayland clients

qtmultimedia

gstreamer Enable audio support via media-libs/gstreamer
qml Build QML/QtQuick bindings and imports
widgets Build the QtMultimediaWidgets module

qtnetwork

gssapi Enable support for GSSAPI (virtual/krb5)
libproxy Use net-libs/libproxy for automatic HTTP/SOCKS proxy configuration

qtpositioning

geoclue Use enhanced location information from app-misc/geoclue
nmea Build plugin for parsing NMEA (National Marine Electronics Association) sentences
qml Build QML bindings

qtquickcontrols

widgets Enable QtWidgets support

qtquickcontrols2

widgets Enable QtWidgets support

qtscript

scripttools Build the QtScriptTools module (requires QtWidgets)

qtscxml

qml Build QML/QtQuick bindings and imports

qtsensors

qml Build QML bindings

qtspeech

flite Enable text-to-speech synthesizer plugin using app-accessibility/flite engine
qml Build QML/QtQuick bindings and imports
speechd Enable text-to-speech synthesizer plugin using app-accessibility/speech-dispatcher engine

qttools

assistant Build Qt Assistant and the QtHelp module
clang Enable using libclang for code parsing (linguist/qdoc)
designer Build Qt Designer
distancefieldgenerator Build Qt Distance Field Generator
linguist Build Qt Linguist (GUI requires USE=widgets)
pixeltool Build Qt Pixeltool
qdbus Build the Qt D-Bus Interface (D-Bus Viewer requires USE=widgets)
qdoc Build Qt Documentation Generator
qml Build QML/QtQuick bindings and imports
qtattributionsscanner Build Qt Source Code Attribution Scanner
qtdiag Build Qt Diag
qtplugininfo Build Qt Plugin Info
widgets Enable QtWidgets support

qtvirtualkeyboard

handwriting Adds handwriting recognition integration support

qtwayland

compositor Enable support for the wayland compositor / server APIs
qml Build QML/QtQuick bindings and imports
vulkan Enable support for Vulkan-based server buffer integration

qtwebchannel

qml Build QML/QtQuick bindings and imports

qtwebengine

designer Install the QWebEngineView plugin used to add widgets in dev-qt/designer forms that display web pages.
jumbo-build Combine source files to speed up build process.
pdfium Build the QtPdf module based on chromium's PDFium library
qml Build QML/QtQuick bindings and imports
system-icu Use the system-wide dev-libs/icu instead of bundled.
widgets Enable QtWidgets support

qtwebsockets

qml Build QML bindings

qtwidgets

gtk Build the GTK platform theme plugin

qtxmlpatterns

qml Build the XmlListModel import for QtQuick (requires QtDeclarative)

dev-ruby

asciidoctor-diagram

barcode Enable diagrams with dev-ruby/rqrcode and dev-ruby/barby
ditaa Enable diagrams with media-gfx/ditaa
lilypond Enable diagrams with media-sound/lilypond
meme Enable diagrams with media-gfx/imagemagick
mscgen Enable diagrams with media-gfx/mscgen
plantuml Enable diagrams with media-gfx/plantuml
tikz Enable diagrams with dev-tex/pgf

barby

cairo Add support for writing images (PNG, PS, EPS and, if supported, PDF and SVG) using dev-ruby/rcairo. Not available on JRuby.
png Add support for writing PNG images using dev-ruby/chunky_png.
prawn Add support for writing PDF documents using dev-ruby/prawn.
qrcode Add support for QRCode 2D codes using dev-ruby/rqrcode.
rmagick Add support for writing images (among others PNG, GIF and JPEG) using dev-ruby/rmagick. Not available on JRuby.

faraday_middleware

mashify Include FaradayMiddleware::Mashify
oauth Include FaradayMiddleware::OAuth
parsexml Include FaradayMiddleware::ParseXml
rashify Include FaradayMiddleware::Rashify

io-event

io-uring Enable io_uring support, and use io_uring instead of epoll

maruku

highlight Enable source code highlighting via dev-ruby/syntax

mysql2

mariadb Use mariadb bindings

net-ssh

chacha20 Use dev-ruby/rbnacl for chacha20-poly1305@openssh.com support
ed25519 Use dev-ruby/ed25519 for Ed25519 support

rrdtool-bindings

graph Enable support for graphing functions

rspec-core

highlight Enable source code highlighting via dev-ruby/coderay

rubygems

server Install support for the rubygems server

vcr

json Add support for casettes serialized with JSON

dev-scheme

bigloo

avahi Enable Avahi support
gpg Enable GPG support
libuv Enable libuv support

gauche

mbedtls Enable support for net-libs/mbedtls

gauche-gl

cg Enable NVidia Cg binding

guile

debug-freelist Include garbage collector freelist debugging code
debug-malloc Include malloc debugging code
deprecated Enable deprecated features
discouraged (implied by deprecated) enable merely discouraged features
networking Include networking interfaces
regex Include regular expression interfaces

kawa

awt Assume AWT is available
frontend Build "kawa" front-end program using sys-libs/readline
jemacs Build JEmacs
krl Build BRL emulation and KRL
sax Assume SAX2 is available with dev-java/sax
servlets Build support for generating servlets with Java servletapi
swing Assume Swing is available

mit-scheme

blowfish Compile with blowfish encryption support

racket

chez Build Racket on Chez (Racket CS)
futures Enable racket/future library for fine-grained hardware parallelism
ncurses Add ncurses support for expeditor (REPL expression editor)
places Enable racket/place library for share-nothing parallelism and message-passing communication. Compared to futures, places are heavyweight, but they have a simpler performance model.
threads Enable support for green threads

scm

arrays Support for arrays, uniform-arrays and uniform-vectors.
bignums Support for large precision integers.
cautious SCM will always check the number of arguments to interpreted closures.
dynamic-linking Be able to load compiled files while running.
engineering-notation Floats to display in engineering notation (exponents always multiples of 3) instead of scientific notation.
gsubr generalized c arguments: for arbitrary (more then 11) arguments to C functions.
inexact Support for floating point numbers.
ioext Commonly available I/O extensions: line I/O, file positioning, file delete and rename, and directory functions.
libscm Build and install libscm.a and related headers
macro C level support for hygienic and referentially transparent macros (syntax-rules macros).
regex String regular expression matching.
unix Support for: nice, acct, lstat, readlink, symlink, mknod and sync.

slib

gambit Support for gambit scheme implementation
scm Support for scm scheme implementation

dev-tcltk

expect-lite

debug pull in packages needed for runtime interactive debugger

tcl3d

ode Enable support for physics engine from dev-games/ode
osg Enable support for 3D toolkit from dev-games/openscenegraph

tktreectrl

shellicon shellicon extension

dev-tex

abntex

lyx Install with app-office/lyx layout

biblatex

biber Install the unicode compatible backend processor

pythontex

highlighting Syntax highlighting using dev-python/pygments

dev-texlive

texlive-basic

luajittex Add support for LuaJitTeX: LuaTeX based on LuaJIT which is usually faster.

dev-util

Tensile

client Build and install tensile_client executable to run benchmarks and tune GPU GEMM

bazel

tools Install extra bazel tools to build from sources

bpftool

caps Use sys-libs/libcap to enable unprivileged run support

bpftrace

fuzzing Build bpftrace for fuzzing

buildbot

docker Add support for worker docker command steps
irc Add support for status delivery through an ircbot.

cargo-audit

fix Add support for 'fix' subcommand (experimental)

catalyst

ccache Enables ccache support
iso Pulls in the depends for building iso images
system-bootloader Pulls in the depends needed to setup livecd bootloader from the host system rather than using a cdtar

ccache

redis Enable Redis backend for storage via dev-libs/hiredis
static-c++ Avoid dynamic dependency on gcc's libstdc++.

cccc

apidoc Build software docs with doxygen/graphviz and metrics with cccc
mfc Add patch for MFC dialect options

cmake

dap Build debugger for CMake with Debug Adapter Protocol support via dev-cpp/cppdap

codeblocks

contrib Build additional contrib components
fortran Build FortranProject plugin which enables to use Code::Blocks IDE for Fortran language

cppcheck

htmlreport install cppcheck-htmlreport

ctags

json Enable JSON output support
xml Enable XML parsing support
yaml Enable YAML parsing support

cwdiff

mercurial install hg wdiff alias for dev-vcs/mercurial

devhelp

gedit Install plugin for app-editors/gedit

dialog

minimal Disable library, install command-line program only

diffoscope

R Use dev-lang/R
binutils Use sys-devel/binutils
cpio Use app-arch/cpio
diff Use sys-apps/diffutils
docx Use app-text/docx2txt
dtc Use sys-apps/dtc
e2fsprogs Use sys-fs/e2fsprogs
file Use sys-apps/file
find Use sys-apps/findutils
gettext Use sys-devel/gettext
gpg Use app-crypt/gnupg
haskell Use dev-lang/ghc
hdf5 Use sci-libs/hdf5
hex Use app-editors/vim-core
iso Use app-cdr/cdrtools
llvm Use sys-devel/llvm
opendocument Use app-text/odt2txt
pascal Use dev-lang/fpc
rpm Use app-arch/rpm
squashfs Use sys-fs/squashfs-tools
ssh Use net-misc/openssh
tar Use app-arch/tar
tcpdump Use net-analyzer/tcpdump
zip Use app-arch/unzip

edi

clang Provide integration with sys-devel/clang and dev-util/bear for autocompletion, inline errors and information about compilation units.

flatpak-builder

yaml Use libyaml for yaml support

geany

vte Enable Terminal support (x11-libs/vte)

geany-plugins

ctags Enable ctags plugin
debugger Enable the debugger plugin which interfaces with sys-devel/gdb
enchant Enable spell checking using enchant
gpg Enable geanypg plugin which integrates GPG using app-crypt/gpgme
gtkspell Use gtkspell for dictionary support in GeanyVC
markdown Enable the markdown plugin
pretty-printer Enable pretty-printer plugin
scope Enable the scope plugin which is a graphical GDB front-end
webhelper Enable webhelper plugin
workbench Enable workbench plugin

glade

gjs Build catalog support for dev-libs/gjs widgets.
webkit Build catalog support for net-libs/webkit-gtk:4 widgets.

global

vim Integrate the GNU GLOBAL source code tag system with Vim

gnome-builder

clang Provide integration with sys-devel/clang for best possible C/C++ autocompletion, semantic highlighting, symbol resolving, and diagnostics support
d-spy Provide D-Bus debugging functionality via dev-util/d-spy
flatpak Enable support for flatpak applications using sys-apps/flatpak
git Provide support for the Git version control system via dev-libs/libgit2-glib (such as setup of Git for New Project, direct cloning for Open Project and changed lines indicators in the editor gutter)
sysprof Provide an integrated profiler via dev-util/sysprof

google-perftools

debug Build a set of libraries with debug support (so-called debugalloc). These are available by default but are not needed unless you're actually developing using tcmalloc.
largepages Use (experimental) larger pages for tcmalloc, this increases memory usage, but should speed up the allocation/free operations.
largepages64k Use (experimental) 64K pages for tcmalloc, this increases memory usage, but should speed up the allocation/free operations.
minimal Only build the tcmalloc_minimal library, ignoring the heap checker and the profilers.
optimisememory To build libtcmalloc with smaller internal caches.

heaptrack

gui Install Qt5-based analyzer tool

hfstospell

clang Use different logic in ebuild when clang is used

intel-graphics-compiler

vc Enable VectorCompiler for a better performance.

intel-graphics-system-controller

cli Build CLI tools for flashing manually a firmware upgrade.

kcov

binutils Use sys-libs/binutils-libs for --verify support

kdevelop

gdbui Enable GUI for attaching GDB to a running process
hex Enable hex editor plugin via app-editors/okteta
qmake Enable support for QMake build system
reviewboard Enable reviewboard support

kernelshark

custom-optimization Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS

kup

gitolite Enable support for dev-vcs/gitolite in kup-server

libabigail

btf Handle reading kernel debug files in BTF format via dev-libs/libbpf

librnp

botan Use Botan crypto backend instead of OpenSSL

ltrace

elfutils Use libdwfl from sys-libs/libunwind for frame unwinding support
unwind Use sys-libs/libunwind for frame unwinding support

lttng-tools

ust Support LTTng-UST (Userspace Tracing)

lttng-ust

numa Enable numa support

massif-visualizer

callgraph Enable detailed snapshot analysis using media-gfx/kgraphviewer

mingw64-runtime

default-ucrt Use ucrt instead of msvcrt-os as the default crt (WARNING: incompatible with each others and also for building Wine with USE=mingw, pick one from the start and keep it)
idl Install idl files
libraries Build extra libraries: mangle, pseh, winpthreads
tools Build extra tools: gendef, genidl, widl

muon

archive Enable extracting wraps using app-arch/libarchive.
libpkgconf Enable looking up packages via dev-util/pkgconf.

nvidia-cuda-toolkit

debugger Install the CUDA debugger
nsight Install profiling and optimizing tools (nsight-compute, nsight-systems)
profiler Install the NVIDIA CUDA profiler (nvprof) and the related libraries
rdma Enable infiniband support via sys-cluster/rdma-core
sanitizer Install compute-sanitizer tool
vis-profiler Install the NVIDIA CUDA visual profiler (nvvp)

oprofile

apidoc Provide doxygen generated API docs.

ostree

archive Use libarchive
dracut Install dracut module
gpg Enable GPG support
grub Enable grub configuration generator
http2 Use http2
httpd Enable ostree trivial-httpd entrypoint
libmount Use libmount
sodium Use libsodium for ed25519
soup Use libsoup for networking

perf

babeltrace Enable dev-util/babeltrace support
bpf Enable support for eBPF features with dev-libs/libbpf
clang Enable builtin clang and LLVM support
doc Build documentation and man pages. With this USE flag disabled, the --help parameter for perf and its sub-tools will not be available. This is optional because it depends on a few documentation handling tools that are not always welcome on user systems.
libpfm Enable dev-libs/libpfm support
libtraceevent Enable dev-libs/libtraceevent support
libtracefs Enable dev-libs/libtracefs support
numa Enable NUMA support
perl Add support for Perl as a scripting language for perf tools.
systemtap Add support to define SDT event in perf tools.
unwind Use sys-libs/libunwind for frame unwinding support.

plan9port

freefonts Don't install BigelowHolmes fonts

poke

nbd Enable poking at networked block devices via sys-libs/libnbd.
pvm-profiling Enable profiling in the PVM

pycharm-community

bundled-jdk Use bundled jdk

pycharm-professional

bundled-jdk Use bundled jdk

ropper

z3 Enable Z3 contraint solver support

scanmem

gui Enable the GameConqueror GUI

sccache

azure Enable Azure Blob Storage support
dist-client Enables distributed support in the sccache client
dist-server Enables the sccache-dist binary
gcs Enable Google Cloud Storage support
redis Enable Redis support
s3 Enable full Amazon S3 support
simple-s3 Enable minimal Amazon S3 support

schroot

btrfs Enable support for chroots using btrfs snapshots
dchroot Enables the building of a wrapper named "dchroot", replacing sys-apps/dchroot
lvm Enable support for chroots using LVM snapshots
zfs Enable support for chroots using ZFS shapshots/clones

sdl-jstest

sdl Enable media-libs/libsdl2 based input test
sdl1 Enable media-libs/libsdl based input test

spirv-llvm-translator

tools Install the command-line translator llvm-spirv

strace

aio Enable dev-libs/libaio support for tracing Asynchronous I/O operations
elfutils Enable stack backtraces (-k flag) via dev-libs/elfutils
unwind Enable stack backtraces (-k flag) via sys-libs/libunwind

sysdig

modules Build kernel modules needed for tracing local events. Disable this only if you intend to use sysdig purely to work with dumpfiles.

sysprof

unwind Use sys-libs/libunwind to unwind the stack

systemtap

libvirt Support probing of libvirt domains.

trace-cmd

udis86 Enable support for dev-libs/udis86 disassembler library

uftrace

capstone Use capstone to provide dynamic tracing without recompilation

vulkan-tools

cube Build the cube/cubepp demos

watchman

python Install pywatchman bindings and the watchman-{wait,make} utils

dev-vcs

cvs

server Enable server support

darcs

curl Use libcurl for HTTP support.
terminfo Use the terminfo package for enhanced console support.
threaded Use threading and SMP support.

fossil

fusefs Enable the Fuse Filesystem
json Enable the JSON API of Fossil's wiki
system-sqlite Use the system SQLite instead of the bundled one
tcl-private-stubs Enable Tcl integration via private stubs mechanism
tcl-stubs Enable Tcl integration via stubs library mechanism
th1-docs Enable TH1 for embedded documentation pages
th1-hooks Enable TH1 hooks for commands and web pages

git

blksha1 Use the new optimized SHA1 implementation
cgi Install gitweb too
curl Support fetching and pushing (requires webdav too) over http:// and https:// protocols
gpg Pull in gnupg for signing -- without gnupg, attempts at signing will fail at runtime!
highlight GitWeb support for app-text/highlight
mediawiki Support pulling and pushing from MediaWiki
perforce Add support for Perforce version control system (requires manual installation of Perforce client)
safe-directory Respect the safe.directory setting
subversion Include git-svn for dev-vcs/subversion support
tk Include the 'gitk' and 'git gui' tools
webdav Adds support for push'ing to HTTP/HTTPS repositories via DAV

git-annex

assistant Enable git-annex assistant and watch command
benchmark Enable benchmarking
dbus Enable dbus support
gitlfs Build with git-lfs library (rather than vendored copy)
magicmime Use libmagic to determine file MIME types
pairing Enable pairing
torrentparser Use haskell torrent library to parse torrent files
webapp Enable git-annex webapp

git-delete-merged-branches

full-name-executable Install executable /usr/bin/git-delete-merged-branches that is in conflict with dev-vcs/git-extras

gitg

glade Install a glade catalog file
python Install Python bindings for those plugins requiring it.

gitolite

contrib Install user-contributed files
tools Install tools to e.g. convert a Gitosis config to gitolite or one to check if your setup is gitolite >= 3.x compatible

gitolite-gentoo

tools Install tools to e.g. convert a Gitosis config to gitolite or one to check if your setup is gitolite >= 3.x compatible

mercurial

chg Support Mercurial command server client
gpg Support signing with GnuPG.
rust Use Rust extensions.
tk Install dev-lang/tk for hgk script.

subversion

extras Install extra scripts (examples, tools, hooks)
kwallet Enable encrypted storage of passwords with kde-frameworks/kwallet
plaintext-password-storage Enable on-disk caching of plaintext passwords and passphrases. (Enabling this functionality will not force Subversion to store passwords in plaintext, but does permit users to explicitly allow that behavior via runtime configuration.)

games-action

beathazardultra

bundled-libs Use the upstream provided bundled libraries.

descent1-freedata

l10n_de Provides German translations for the game's briefings, robot descriptions, and outro of the original campaign
opl3-musicpack Include alternate version of the game's music, recorded with the Yamaha YMF262 OPL3 soundchip
sc55-musicpack Include alternate version of the game's music, recorded with the Roland Sound Canvas SC-55 MIDI module
textures Include high resolution (640x480) backgrounds, briefing images and fonts (Descent 1)

descent2-freedata

l10n_de Provides German translations for the game's briefings, robot descriptions, and outro of the original campaign
opl3-musicpack Include alternate version of the game's music, recorded with the Yamaha YMF262 OPL3 soundchip
sc55-musicpack Include alternate version of the game's music, recorded with the Roland Sound Canvas SC-55 MIDI module

dxx-rebirth

d1x Install Descent 1 resources and executable
d2x Install Descent 2 resources and executable
data Ensure some game levels are present; if the full game's level data is not already installed then install the playable demo data (i.e. shareware levels)
debug Enable various debugging code paths and sanity checks, not just output. Some of these checks date back to the retail build, and choke on some custom levels because the game was never coded to sufficiently distrust inputs
editor Enable level editor support
l10n_de Provides German translations for the game's briefings, robot descriptions, and outro of the original campaign
midi Enforce that SDL-mixer is used and has midi support
music Enable music support
opl3-musicpack Include alternate version of the game's music, recorded with the Yamaha YMF262 OPL3 soundchip
sc55-musicpack Include alternate version of the game's music, recorded with the Roland Sound Canvas SC-55 MIDI module
sdl2 Use libSDL2, SDL2-mixer instead of libSDL-1* and SDL-mixer-1*
tracker Enable support for the PHP-based multiplayer game tracker

hotline-miami

bundled-libs Use bundled libraries.
launcher Install qt launcher

minetest

client Build Minetest client
leveldb Enable LevelDB backend
prometheus Enable prometheus client support
redis Enable redis backend via dev-libs/hiredis
server Build Minetest server
spatial Enable SpatialIndex AreaStore backend

prismlauncher

lto Enable link-time optimization
qt6 Build with Qt6 support instead of the default Qt5

supermariowar

server Compile and install Super Mario War server files

supertuxkart

nettle Use dev-libs/nettle crypto backend
recorder Enable recording with media-libs/libopenglrecorder
sqlite Record IP bans, statistics in server mode with dev-db/sqlite
wiimote Support for wiimote input devices

swordandsworcery

bundled-libs Use the upstream provided bundled libraries.

trine

launcher Install GTK+ launcher

trine-enchanted-edition

launcher Install GTK+ launcher

trine2

launcher Install GTK+ launcher

games-arcade

bomns

editor enables building the level editor

burgerspace

network Enable client-server support

commandergenius

downloader Allows some Keen games to be downloaded from the menu

jazz2

server Build the multiplayer game server

jazz2-data

cc Install The Christmas Chronicles additional data
demo Use the free demo data instead of the full retail game data

lbreakout2

themes Install additional themes

moleinvasion

music Download and install the music files

oshu

osu-skin Include more complete osu-skin (other is minimal)

performous

midi Enable MIDI I/O support
songs Install a few demo songs
webcam Enable Webcam support

tuxanci

physfs Use dev-games/physfs instead of dev-libs/libzip to load compressed data

games-board

cockatrice

client Build with client
oracle Build with oracle
server Compile server support

crafty

no-opts Don't try to enable crazy CFLAG options

freedoko

backgrounds Install additional background images
gnomecards Install the gnome-games card set
kdecards Install the KDE card set
openclipartcards Install the openclipartcards card set
pysolcards Install the PySol card set
xskatcards Install the XSkat card set

pasang-emas

extras Install some extra themes

pioneers

help Enable gnome ingame help via scrollkeeper

pysolfc

extra-cardsets Install extra cardsets
sound Enable sound support using dev-python/pygame

scid

photos Install collection of player photos (large)
scripts Install additional python and tcl utility scripts

stockfish

general-32 Generic unoptimized 32-bits build
general-64 Generic unoptimized 64-bits build
optimize Enable upstream -O3 optimizations (default enabled)

tablebase-syzygy

6-pieces Install tablebases for 6 pieces (huge!)

xboard

default-font Install the default font that xboard uses
zippy Enable experimental zippy client

games-emulation

atari800

encode-mp3 Support recording sound in MP3 format

desmume

gdb Enable support for the remote GDB stub
openal Use media-libs/openal for microphone input
wifi Enable support for Wi-Fi (experimental and discouraged)

dolphin

discord-presence Enables Discord Rich Presence, show the current game on Discord
evdev Enable evdev input support
log Increase logging output
mgba Enables GBA controllers emulation using libmgba.

dosbox

core-inline Enable memory-increasing inlines for better performance but requiring more build time
glide Enable unofficial Glide emulation via media-libs/openglide

dosbox-staging

dynrec Use recompiling cpu core instead of dynamic x86/x64 specific cpu core
fluidsynth use media-sound/fluidsynth for MIDI emulation
mt-32 use media-libs/munt-mt32emu for MT-32 emulation
network Enable networking features (modem, ipx)
screenshot Enable screenshots of rendered output using media-libs/sdl2-image
slirp Enable Ethernet emulation using net-libs/libslirp

fceux

archive Use app-arch/libarchive for 7zip support
ffmpeg Use media-video/ffmpeg for video recording
x265 Use media-libs/x265 for video recording (HEVC)

generator

sdlaudio Enable SDL Audio

hatari

capsimage Use dev-libs/spsdeclib to read .IPF, .RAW, and .CTR disk images
portmidi Use media-libs/portmidi as an alternative MIDI backend

higan

gtk Use GTK3 (Qt5 if disabled) user interface backend

jgemu

bsnes Install bsnes for Super Nintendo
cega Install Cega for SG-1000, Sega Master System and Game Gear
gambatte Install Gambatte for Game Boy and Game Boy Color
geolith Install Geolith for Neo Geo AES/MVS
jollycv Install JollyCV for ColecoVision
mednafen Install Mednafen for Atari Lynx, Nintendo Virtual Boy, NEC PC Engine, NEC SuperGrafx, Sony PlayStation, Sega Saturn, Super Nintendo, Neo Geo Pocket and WonderSwan
melonds Install MelonDS for Nintendo DS
mgba Install mGBA for Game Boy Advance
nestopia Install Nestopia for Nintendo Entertainment System
prosystem Install ProSystem for Atari 7800
sameboy Install SameBoy for Game Boy and Game Boy Color
vecx Install Vecx for Vectrex

m64py

7z Ensure support for .7z archives.
rar Ensure support for .rar archives.

mgba

discord Enable Discord RPC support
elf Enable the use of elf utils via dev-libs/elfutils
gles2 Build OpenGL ES 2.x RenderSystem
gles3 Build OpenGL ES 3.x RenderSystem
libretro Build libretro port

mupen64plus

audio-sdl Enable SDL audio plugin.
input-sdl Enable SDL input plugin.
rsp-hle Enable HLE RSP plugin.
ui-console Enable default console UI.
ui-m64py Enable PyQt5 UI using games-emulation/m64py.
video-glide64mk2 Enable Glide64mk2 video plugin.
video-rice Enable Rice video plugin.

mupen64plus-core

debugger Build the debugger
new-dynarec Enable new experimental dynamic recompiler implementation (only for x86 and arm)
opencv Support video capture via media-libs/opencv
osd Overlay emulator messages using on-screen-display

mupen64plus-video-glide64mk2

hires Support hi-resolution textures (requires dev-libs/boost)

pcsx2

sndio Enable support for the media-sound/sndio backend

ppsspp

discord Enable interfacing with a locally running Discord desktop client

snes9x

libretro Build libretro port
netplay Enable playing ROMs over the network (not recommended)

vbam

link Enable GBA linking functionality

games-engines

devilutionx

sodium Enable network packet encryption using dev-libs/libsodium
zerotier Enable ZeroTier for online public games

exult

fluidsynth Compile with support for FluidSynth
tools Enable tools, usercode compiler and mods support

fheroes2

tools Install development tools like 82m2wav and xmi2midi.

frobtads

tads2compiler Build TADS2 compiler
tads3compiler Build TADS3 compiler

love

gme Use media-libs/game-music-emu to support additional music formats

odamex

client Build client target
hidpi Use bundled FLTK 1.4, which has better support for HiDPI screens
master Build master server target (advertises odamex server list)
odalaunch Build the wxWidgets based launcher
portmidi Enable PortMidi support
server Build server target

openmw

devtools Install development tools like bsatool, esmtool and opencs.
osg-fork Use OpenSceneGraph forked by OpenMW instead of upstream OSG.

scummvm

fluidsynth compile with support for fluidsynth
fribidi Support for right-to-left languages via dev-libs/fribidi
glew enable support for OpenGL Extension Wrangler Library (media-libs/glew)
mpeg2 enable mpeg2 codec for cutscenes
net enable cloud support via media-libs/sdl2-net
sndio Enable support for MIDI music using media-sound/sndio
speech enable text-to-speech support through app-accessibility/speech-dispatcher
unsupported enable unsupported and/or broken game engines (you're on your own)

scummvm-tools

tremor Enable tremor, a fixed-point version of the Ogg Vorbis decoder

solarus

doc Install doxygen developer documentation.

games-fps

alienarena

vidmode Link against x11-libs/libXxf86vm. Required for full-screen support.

chocolate-doom

midi basic support for MIDI files

darkplaces

cdsound Enables using CD audio in the engine
demo Uses the demo data from quake1 (quake1-demodata)
lights Install and setup the updated light maps
textures Install and setup the updated textures

doomsday

demo Install launcher dor doom1.wad from games-fps/doom-data
display-mode Include the ability to set the display mode
fluidsynth Build the FluidSynth sound driver
freedoom Install launcher for doom1.wad from games-fps/freedoom
tools Build additional tools such as doomsday-shell, md2tool and texc

duke3d-data

demo Extract data files from the shareware version.
gog Extract data files from the GOG.com version.

eduke32

duke3d Install the Duke Nukem 3D data files, provided by games-fps/duke3d-data.
fluidsynth Install media-libs/sdl2-mixer with fluidsynth support.
hrp Install the Duke Nukem 3D High Resolution Pack.
offensive Install the Duke Nukem 3D XXX Pack.
opl Install the Duke Nukem 3D OPL music files.
psx Install the Duke Nukem 3D PSX high resolution voice files.
sc-55 Install the Duke Nukem 3D Roland SC-55 music files.
sdk Install the SDK files.
server Enable support for multiplayer.
tools Install the support tools for mapster32.
voidsw Enable support for Shadow Warrior (Classic) through VoidSW.
voxels Install the Duke Nukem 3D Voxels Pack.
vpx Enable support for media-libs/libvpx.
xmp Enable support for media-libs/exempi.

gzdoom

gles2 Enable GLES2 backend
non-free Enable non-free components
swr Enable software renderer

nexuiz

maps Install the community map pack

prboom-plus

dumb Enable support for various tracker-style music formats via media-libs/dumb
fluidsynth Enable support for MIDI via media-sound/fluidsynth
net Enable support for network play
portmidi Enable support for MIDI via media-libs/portmidi
sdl2-image Enable support for high-resolution texture support via media-libs/sdl2-image
sdl2-mixer Enable support for MIDI via media-libs/sdl2-mixer
server Build PrBoom-Plus server

quake2-icculus

demo Install the demo files (quake2-demodata) and configure for use
qmax Build the pretty version (quake max)
rogue Build support for the 'Ground Zero' Mission Pack (rogue)
xatrix Build support for the 'The Reckoning' Mission Pack (xatrix)

quakeforge

client Build Normal and QuakeWorld clients alongside the servers
wildmidi Use media-sound/wildmidi for midi support

redeclipse

dedicated Install only as a dedicated game server

rott

demo Install the shareware version

sauerbraten

server Compile server support

turtlearena

mumble Adds player-location (positional audio) support to VoIP
server Build server target
voice Adds VoIP support

urbanterror

altgamma Alternative way for gamma setting with modesetting driver
client Build binary for client (includes code for non-dedicated server)
mumble Use Mumble for ingame VoIP (experimental)
server Build binary for dedicated server
skeetshootmod Build support for skeetshoot mod for specific maps
voip Use ioq3 ingame VoIP (experimental)

worldofpadman

maps Install extra maps (PadPack)

xonotic

ode Enable support for physics engine from dev-games/ode

yamagi-quake2

client Build client
ctf Build support for the 'Capture The Flag' addon
gles Build GLES3 renderer
rogue Build support for the 'Ground Zero' Mission Pack
softrender Build software renderer
vulkan Build experimental Vulkan renderer
xatrix Build support for the 'The Reckoning' Mission Pack

games-kids

gcompris

kiosk Enable kiosk mode by default (for use by small children or on a self-service host machine)

games-misc

ponysay

fish-completion Enable fish completion support
non-free Install non-free ponies (i.e. from the MLP franchise)

xcowsay

fortune Enable support for fortune cookies via games-misc/fortune-mod

games-mud

tf

atcp enable ATCP support.
gmcp enable GMCP support.
option102 enable telnet option 102 support.

games-puzzle

gnome-tetravex

cli Build the gnome-tetravex-cli command-line interface
gui Build the gnome-tetravex graphical Gtk user interface

nightsky

bundled-libs Use the upstream provided bundled libraries.

pingus

music Enable playing of background music

tiny-and-big

bundled-libs Use the upstream provided bundled libraries.

world-of-goo-gog

bundled-libs Use bundled libs

world-of-goo-hb

bundled-libs Use bundled libs

games-roguelike

FTL

bundled-libs Use bundled libraries.

angband

sound Enable and install sounds

stone-soup

advpng Use alternate png optimization.
ncurses Enable for console (uses ncurses) based build. (can be enabled on top of tiles)
tiles Enable for graphical (tiled) build. (can be enabled on top of ncurses)

tomenet

client Compile client
server Compile server

games-rpg

daimonin-client

music Install extra music

deponia-doomsday

bonus Install the bonus content (Art Book, Concept Art, Soundtrack)

drascula

sound Install optional audio files

dreamweb

doc High-resolution scans of the written material in the original UK game box

freedroidrpg

devtools Compile the additional dev tools
profile Enable the integration of the ingame real-time profiler

hatoful-boyfriend

gui Install the GUI for configuring screen resolution and input

hatoful-boyfriend-holiday-star

gui Install the GUI for configuring screen resolution and input

kqlives

cheats Enable cheating mode

manaplus

mumble Enable support for voice chat
pugixml Use dev-libs/pugixml for XML parsing isntead of dev-libs/libxml2
sdl2 Use libsdl2 instead of libsdl

sumwars

tools Builds editor tools

the-longest-journey

hd Install high definition backgrounds and sprites
hd-fmv Install upscaled full motion videos

to-the-moon

bundled-libs Use bundled libraries

games-simulation

corsix-th

midi Adds support for background MIDI music via SDL_mixer
tools Build tools for decoding RNC files

flightgear

dbus Enable screensaver DBus interaction
gdal Enable alternative terrain engine based on pagedLOD using sci-libs/gdal
qt5 Build Qt5 launcher application
udev Enable event-based Input devices through virtual/udev
utils Build various utilities (fgpanel, fgviewer among others)

openrct2

scripting Enable the dev-lang/duktape scripting engine for executing user scripts.

openttd

allegro Add support for Allegro
dedicated Build only the openttd server, and not the client.
fluidsynth Compile with support for FluidSynth
lzo Enables LZO compression for savegames. This is only needed to load extremely old savegames. (versions before 0.2)
openmedia Enables the free open media sets: OpenGFX, OpenSFX, OpenMSX, removing the requirement for proprietary TTD assets to play OpenTTD.

simutrans

midi support for background MIDI music via media-sound/fluidsynth
minimal Don't install any PakSets (scenario data)

simutrans-paksets

128 Install higher resolution scenario data (128 px graphics)
comic192 Install comic-like scenario data (192 px graphics)
cs128 Install Czech-Slovak scenario data (128 px graphics)
excentrique48 Install eccentric scenario data (48 px graphics)
german128 Install German scenario data (128 px graphics)
nippon64 Install Nippon scenario data (64 px graphics)

train-valley

gui Install the GUI for configuring screen resolution and input

games-sports

speed-dreams

osggraph Enable the new work-in-progress 3D engine using dev-games/openscenegraph
webstats Enable support for sending racing statistics to a web server (experimental)

xmoto

double-precision more precise calculations at the expense of speed

games-strategy

0ad

editor Include Atlas scenario editor projects
lobby Enable the use of net-libs/gloox and the multiplayer lobby
nvtt Support for some uncompressed data formats (might be needed for some mods)

colobot

devbuild TODO
tools Build tools

colobot-data

music Enable music support

defcon-demo

system-libs Use system libraries instead of the ones included in the upstream distribution.

freeciv

aimodules Support for dynamically loadable AI modules (server-side)
auth Add authentication capability via mysql, postgres, or sqlite3
gtk3 Build the gtk3 client
gtk4 Build the gtk4 client
json Add support for JSON via dev-libs/jansson
mapimg Additional mag image toolkit via media-gfx/imagemagick
modpack Build the freeciv-modpack-program to download/install mods
rule-editor Build ruleset editor
server Enable server support. Disabling this will also make it impossible to start local games.
sound Add support for sound provided by media-libs/sdl-mixer
system-lua Use dev-lang/lua instead of the bundled liblua
web-server Build the freeciv-web server in place of the freeciv server

freeorion

client Build game client

freesynd

devtools Build development tools

hedgewars

server Enable local server

ja2-stracciatella

editor Adds necessary file to run the editor
ru-gold Support for russian gold ja2 version

megaglest

editor Build map editor
fribidi Enable FriBIDi support
model-viewer Build model viewer
streflop Use the library streflop. Out of synchs may occur if not enabled.
tools Build model import/export tools
unicode Use unicode strings for wxwidgets
wxuniversal Use the wxUniversal port which implements the various GUI controls by drawing them itself

satellite-reign

gui Install the GUI for configuring screen resolution and input

ufoai

client Build the main game client
server Build the dedicated server

uqm

music download and install original 3DO music files
remix download and install remixed music files (large)
voice download and install voice files (large)

wargus

bne Support extracting data from the Battle.net Edition

warzone2100

discord Enable Discord presence/join integration

wesnoth

server Enable compilation of server

games-util

basis_universal

opencl Enable OpenCL support

gslist

web Enable the web interface

lgogdownloader

gui Enable GUI login support for passing reCAPTCHA

slade

fluidsynth Enable MIDI software synthesis using media-sound/fluidsynth

wit

fuse Enable image mount support via fuse

gnome-base

gdm

bluetooth-sound Allow loading of bluetooth sound modules. This may be necessary for accessibility screen readers, but may cause bluetooth sound issues for users logging in.
fprint Enables experimental fingerprint authentication using sys-auth/fprintd
plymouth Enable support for smooth transition from sys-boot/plymouth

gnome

classic Install gnome-extra/gnome-shell-extensions for the Gnome Shell Classic mode
extras Install additional GNOME applications

gnome-applets

tracker Build the tracker search bar applet

gnome-control-center

gnome-online-accounts Enable configuration panel for net-libs/gnome-online-accounts accounts
ibus Enable support for enhanced input methods through app-i18n/ibus

gnome-extra-apps

games Install Gnome Games
share Install the gnome-extra/gnome-user-share personal file sharing tool
shotwell Install the media-gfx/shotwell photo manager
tracker Install the app-misc/tracker indexer and the GNOME packages that require it

gnome-keyring

ssh-agent Use GNOME Keyring to unlock SSH keys. Recommended unless you are using ECDSA or Ed25519 keys.

gnome-light

gnome-shell Install gnome-base/gnome-shell and x11-wm/mutter for the standard GNOME 3 desktop mode

gnome-session

elogind Support sys-auth/elogind for session tracking

gnome-settings-daemon

elogind Rely on sys-auth/elogind as runtime logind provider
modemmanager Enable WWAN support via net-misc/modemmanager
systemd Rely on sys-apps/systemd as runtime logind provider

gnome-shell

elogind Use sys-auth/elogind for session tracking and suspend support.
ibus Enable support for enhanced input methods through app-i18n/ibus
pipewire Use pipewire to enable the camera monitor

gvfs

afp Enables support for accessing AFP (Apple Filing Protocol) network shares
archive Enables support for accessing files in archives transparently via app-arch/libarchive
bluray Enable playback of Blu-ray filesystems using media-libs/libbluray
elogind Use sys-auth/elogind for session tracking.
fuse Enables fuse mount points in $HOME/.gvfs for legacy application access
gnome-online-accounts Enable configuration panel for net-libs/gnome-online-accounts accounts
google Enables support for accessing Google accounts via dev-libs/libgdata
http Enable the HTTP/DAV backend using net-libs/libsoup
nfs Enable NFS client support via net-fs/libnfs.
udev Enable udev base replacement code for cdda feature

libgnomecanvas

glade Enable glade support

librsvg

tools Build svg viewer tool

nautilus

cloudproviders Enable the cloudproviders support
gstreamer Enable the Audio/Video file properties page
previewer Use gnome-extra/sushi to preview files from the file mananger
sendto Enable the nautilus-sendto extension to send files to various locations/devices

gnome-extra

cinnamon-control-center

gnome-online-accounts Enable configuration panel for net-libs/gnome-online-accounts accounts
modemmanager Enable support for mobile broadband devices using net-misc/modemmanager

cjs

sysprof Enable profiling data capture support using dev-util/sysprof-capture

eiciel

nautilus Build gnome-base/nautilus extension

evolution-data-server

berkdb sys-libs/db support needed to migrate old (pre-3.13 evolution versions) addressbook data
gnome-online-accounts Enable net-libs/gnome-online-accounts based Google authentication support
oauth Enable internal OAuth2 authentication support for Google and Outlook.com. If gnome-online-accounts is enabled a nd used, this is not necessary, but both can be supported at the same time with different setup at runtime
oauth-gtk3 Enable internal OAuth2 authentication for GTK+3 applications (libedataserverui-*.so) support for Google and Outlook.com. If gnome-online-accounts is enabled and used, this is not necessary, but both can be supported at the same time with different setup at runtime
oauth-gtk4 Enable internal OAuth2 authentication for GTK 4 applications (libedataserverui4-*.so) support for Google and Outlook.com. If gnome-online-accounts is enabled and used, this is not necessary, but both can be supported at the same time with different setup at runtime
weather Enable optional weather calendar support

gnome-commander

gsf Add metadata support for OLE, OLE2 and ODF
pdf Add metadata support for PDF
taglib Add metadata support for ID3, Vorbis, FLAC and APE

gnome-contacts

gnome-online-accounts Enable net-libs/gnome-online-accounts based Google authentication support

gnome-network-displays

firewalld Install firewalld zones

gnome-shell-extension-gsconnect

nautilus Install Nautilus extension for sending files via GSConnect

gnome-software

firmware Enable firmware update support through sys-apps/fwupd
flatpak Enable support for flatpak applications using sys-apps/flatpak
sysprof Enable profiling data capture support using dev-util/sysprof-capture

gnome-system-monitor

systemd Display sys-apps/systemd metadata, e.g. unit names, for running processes

libgda

canvas Enable support for x11-libs/goocanvas
http Enable embedded net-libs/libsoup based server
json Enable support for JSON format
mdb Enable support for Microsoft Access database using app-office/mdbtools
sourceview Enable support for x11-libs/gtksourceview

libgsf

gtk Enable use of gdk in thumbnailer

nemo

tracker Add support for app-misc/tracker search

nm-applet

modemmanager Enable support for mobile broadband devices using net-misc/modemmanager
teamd Enable teamd configuration editor

gnustep-apps

gemas

projectcenter Build and install plugin for gnustep-apps/projectcenter

gworkspace

gwmetadata Enable the metadata indexing and searching system

sogo

activesync Build the ActiveSync support code
sodium Enable support for Argon2 password schemes using dev-libs/libsodium

gnustep-base

gnustep-back-art

xim Enable X11 XiM input method

gnustep-back-cairo

xim Enable X11 XiM input method

gnustep-back-xlib

xim Enable X11 XiM input method

gnustep-gui

speech Audio support using app-accessibility/flite

gnustep-make

libobjc2 Enables use of the GNUstep Objective-C runtime (gnustep-base/libobjc2) with non-fragile ABI and sys-devel/clang compiler
native-exceptions Enables use of the native Objective-C exception support (@try/@catch/@finally) built-in objective-c exceptions with compilers that support it

libobjc2

boehm-gc Enable Hans Boehm's garbage collector (dev-libs/boehm-gc). Not recommended by upstream

gui-apps

foot

grapheme-clustering Enable grapheme clustering support

grim

jpeg Enable JPEG support.

gtkgreet

layershell Enable layer shell support

kanshi

varlink Enable remote control with varlink

mako

icons Enable support for icons

swaybg

gdk-pixbuf Support image types other than PNG

swayidle

elogind Enable support for rootless session via elogind

swaylock

gdk-pixbuf Enable additional image format support via the x11-libs/gdk-pixbuf library

waybar

evdev Enable libevdev support for evdev related features
experimental Enable experimental features, such as Bluetooth battery reporting
libinput Enable libinput support for libinput related features
logind Enable support for logind (bluetooth and idle inhibit)
mpd Enable support for the Music Player Daemon
mpris Enable support for mpris
network Enable libnl support for network related features
pipewire Enable support for pipewire
popups Enable popup support with gtk-layer-shell
pulseaudio Enable support for volume control via PulseAudio
sndio Enable support for volume control via sndio
tray Enable support for tray
wifi Enable support for wifi/rfkill

waypipe

dmabuf Use DMABUFs for data exchange and hardware decoding
ffmpeg Link with ffmpeg to allow buffer displays using video streams
systemtap Enable SystemTAP/DTrace tracing

wayvnc

gbm enable GPU-side screencopy (experimental)
tracing Trace kernel and memory calls

gui-libs

gtk

broadway Enable the GDK Broadway backend.
cloudproviders Enable GtkPlacesSidebar to access cloud services
colord Use x11-misc/colord for color management in printing
sysprof Enable profiling data capture support using dev-util/sysprof-capture

gtksourceview

sysprof Enable profiling data capture support using dev-util/sysprof-capture

libhandy

glade Install module and catalog for dev-util/glade

neatvnc

examples Build and install examples
gbm Enable support for the Generic Buffer Manager (gbm)
h264 Enable H.264 encoding
jpeg Enable JPEG compression
tracing Trace kernel and memory calls
websockets Enable websockets support

vte

icu Enable legacy charset support using dev-libs/icu
systemd Support moving terminal child processes to their own systemd user scopes to avoid terminal getting killed due to child causing OOM

vte-common

systemd Support moving terminal child processes to their own systemd user scopes to avoid terminal getting killed due to child causing OOM

wlroots

X Enable support for X11 applications (XWayland)
drm Enable Direct Rendering Management
libinput Enable support for input devices via dev-libs/libinput
liftoff Enable support for libliftoff KMS plane backend
session Enable session support (is required for DRM and libinput)
tinywl Install the minimal wayland client, tinywl
x11-backend Enable support for handling input/output devices through x11-libs/libxcb
xcb-errors Better error reporting when using xwayland

xdg-desktop-portal-wlr

elogind Enable support for rootless session via elogind

gui-wm

gamescope

pipewire Enable screen capture via PipeWire
wsi-layer Enable the WSI layer (required for HDR)

hikari

X Enable support for X11 applications (XWayland)

hyprland

legacy-renderer Enable legacy renderer

sway

X Enable support for X11 applications (XWayland)
grimshot Install 'grimshot': script for taking screenshots
swaybar Install 'swaybar': sway's status bar component
swaynag Install 'swaynag': shows a message with buttons
tray Enable support for StatusNotifierItem tray specification
wallpapers Install sway's default wallpaper image

wayfire

gles use libglvnd to do animations more efficiently
system-wfconfig use the system-wide wf-config, else build it as a submodule. DO NOT DISABLE UNLESS YOU KNOW WHAT YOU ARE DOING.
system-wlroots use the system wide wlroots, else build it as a submodule. DO NOT DISABLE UNLESS YOU KNOW WHAT YOU ARE DOING.

kde-apps

akonadi

designer Install plugin for dev-qt/designer
kaccounts Enable support for system-wide defined KAccounts
tools Install tools for developers and testing

akregator

speech Enable text-to-speech support

analitza

eigen Enable dev-cpp/eigen mathematical templates support

ark

zip Enable ZIP archive support via dev-libs/libzip

cantor

R Enable dev-lang/R backend support
analitza Enable kde-apps/analitza backend support
julia Enable dev-lang/julia backend support
qalculate Enable sci-libs/libqalculate backend support

dolphin

activities Track which folders are frequently accessed on a Plasma desktop

gwenview

activities Enable kactivities support
fits Enable support for NASA's sci-libs/cfitsio library
mpris Enable support for MPRIS2 interface, requiring dev-qt/qtdbus as dependency.
share Enable support for a share menu using kde-frameworks/purpose

k3b

webengine Use dev-qt/qtwebengine for fancy k3bdiskinfoview

kaccounts-providers

webengine Enable Nextcloud KAccounts plugin using dev-qt/qtwebengine

kalarm

pim Enable birthday import, email functions etc. using kde-apps/akonadi
speech Enable text-to-speech support

kalzium

editor Enable the embedded molecule editor/viewer
solver Enable the equation solver

kanagram

speech Enable text-to-speech support

kate-addons

filebrowser Enable File System browser tool view
lspclient Enable LSP (Language Server Protocol) client plugin
projects Enable Project plugin for executing queries on SQL DBs
snippets Enable Snippets Tool View plugin to manage or download code snippets
sql Enable SQL plugin for executing queries on SQL DBs

kate-lib

activities Enable Plasma Activities support via kde-frameworks/kactivities

kde-apps-meta

accessibility Pull in kde-apps/kdeaccessibility-meta packages
admin Pull in kde-apps/kdeadmin-meta packages
education Pull in kde-apps/kdeedu-meta packages
games Pull in kde-apps/kdegames-meta packages
graphics Pull in kde-apps/kdegraphics-meta packages
multimedia Pull in kde-apps/kdemultimedia-meta packages
network Pull in kde-apps/kdenetwork-meta packages
pim Pull in KDE PIM suite
sdk Pull in developer-specific meta-packages
utils Pull in kde-apps/kdeutils-meta packages

kdeadmin-meta

cron Installs KDE application for virtual/cron configuration

kdecore-meta

share Install kde-frameworks/purpose for share file context menu actions in kde-apps/dolphin
thumbnail Install kde-apps/ffmpegthumbs and kde-apps/thumbnailers for thumbnail generation in kde-apps/dolphin
webengine Enable www-client/falkon which depends on dev-qt/qtwebengine

kdeedu-meta

webengine Enable packages requiring dev-qt/qtwebengine

kdegraphics-meta

color-management Enable color management via media-libs/opencolorio

kdemultimedia-meta

cdrom Include packages for optical discs

kdenetwork-meta

bittorrent Pull in net-p2p/ktorrent for BitTorrent protocol support
dropbox Enable support for Dropbox in kde-apps/dolphin via kde-apps/dolphin-plugins-dropbox
samba Enable support for net-fs/samba file sharing plugin from within file properties
telepathy Enable support for Plasma Telepathy (instant messaging) integration via kde-apps/plasma-telepathy-meta
webengine Enable support for Google Drive integration via kde-misc/kio-gdrive

kdenlive

designer Build plugins for dev-qt/designer
share Enable support for a share menu using kde-frameworks/purpose

kdepim-addons

importwizard Enable additional import plugins for kde-apps/akonadi-import-wizard
markdown Enable Markdown support via app-text/discount

kdepim-meta

bogofilter Install mail-filter/bogofilter for spam filter support in kde-apps/kmail
clamav Install app-antivirus/clamav for virus detection support in kde-apps/kmail
spamassassin Install mail-filter/spamassassin for spam filter support in kde-apps/kmail

kdepim-runtime

speech Enable text-to-speech support

kdesdk-meta

git Enable support for Git VCS in kde-apps/dolphin via kde-apps/dolphin-plugins-git
mercurial Enable support for Mercurial VCS in kde-apps/dolphin via kde-apps/dolphin-plugins-mercurial
subversion Enable support for Apache Subversion VCS in kde-apps/dolphin via kde-apps/dolphin-plugins-subversion
webengine Enable dev-util/kdevelop, requiring dev-qt/qtwebengine

kdeutils-meta

7zip Install app-arch/p7zip for 7zip archive support in kde-apps/ark
floppy Install kde-apps/kfloppy to format and create DOS or ext2fs filesystems in a floppy.
gpg Install kde-apps/kgpg which depends on kde-apps/akonadi
lrz Install app-arch/lrzip for LRZ archive support in kde-apps/ark
rar Install one of app-arch/rar, app-arch/unrar or app-arch/unar for RAR archive support in kde-apps/ark
webengine Enable kde-apps/kimagemapeditor, requiring dev-qt/qtwebengine

kget

bittorrent Enable bittorrent transfer plugin through net-libs/libktorrent
gpg Enable signature verification by GpgME++ via app-crypt/gpgme
mms Enable MMS (Microsoft Media Server) plugin through media-libs/libmms

kig

geogebra Support files created by sci-mathematics/geogebra-bin
scripting Support Python scripting

kio-extras

X Enable support for XCursor thumbnails via x11-libs/libX11
activities Enable activities KIO worker and fileitem plugin
ios Enable AFC (Apple File Conduit) KIO worker for iOS devices support
man Enable manpages KIO worker
nfs Enable NFS support using net-libs/libtirpc
phonon Enable file audio preview plugin using media-libs/phonon
sftp Enable SFTP protocol support using net-libs/libssh
taglib Enable audio thumbnails via media-libs/taglib

kleopatra

pim Enable WKS publishing support using kde-apps/kmail

kmag

keyboardfocus Enable keyboard focus tracking

kmail

speech Enable text-to-speech support

knights

speech Enable text-to-speech support

konqueror

activities Enable kactivities support
speech Build text-to-speech plugin

kopete

addbookmarks Automatically add incoming urls to bookmarks.
autoreplace Automatically replace selected text
contactnotes Enables writing personal notes for contacts.
gadu Enable the Gadu protocol handler.
groupwise Enable the Groupwise protocol handler.
highlight Allows you to specify highlights on specific events.
history Enables saving chat history.
latex Embed latex formatted text into messages.
meanwhile Enable the Sametime protocol handler.
nowlistening Shows song you currently listen to in your status/etc. Bindings for many players.
otr Allows crypting your chat (drugs and talking nonsense are considered as good alternatives ;]).
pipes Send messages to external pipe.
privacy Filter for incoming messages
statistics Everybody loves statistic graphs, especially cake ones. ;]
testbed Enable the testbed protocol.
texteffect Various fancy text effects for your messages (don't ever consider writing us with this enabled ;]).
translator Translate incoming and outgoing messages.
urlpicpreview Enables in conversation pictures preview.
webpresence Show your status and some more information on web.
winpopup Enable pop-up messages sending on windows. (same as good old "net send" messages ;])
zeroconf Enable Link-Local Messaging via the bonjour protocol.

kpimtextedit

designer Build plugins for dev-qt/designer
speech Enable text-to-speech support

krdc

activities Enable Plasma Activities support via kde-frameworks/kactivities

ksystemlog

kdesu Run as root using kdesu from kde-plasma/kde-cli-tools

ktouch

X Enable support for X11 Keyboard Layout Detection

ktp-accounts-kcm

experimental Enables disabled telepathy services (currently only steam)

ktp-common-internals

otr Enable support for encrypted conversations using Off-The-Records messaging
sso Enable support for Single sign-on through KAccounts

ktp-text-ui

speech Enable incoming messages to be read out using text-to-speech

kwave

qtmedia Enable playback via Qt5Multimedia

libkdepim

designer Build plugins for dev-qt/designer

libkleo

fancyviewer Use kde-apps/kpimtextedit for an improved audit log viewer

libksane

kwallet Enable encrypted storage of passwords with kde-frameworks/kwallet

libksieve

speech Enable text-to-speech support

mailcommon

designer Build plugins for dev-qt/designer

marble

aprs Enable support for APRS data sources
designer Install plugin for dev-qt/designer
geolocation Enable position information via dev-qt/qtpositioning
pbf Enable OpenStreetMap PBF file support via dev-libs/protobuf
phonon Enable sound support via media-libs/phonon
shapefile Enable support for ESRI shapefiles
webengine Use dev-qt/qtwebengine for embedded web browser

messagelib

speech Enable text-to-speech support

okular

crypt Enable support for password-encrypted documents via kde-frameworks/kwallet
epub Enable E-Book support via app-text/ebook-tools
image-backend Enable image viewing support
markdown Enable Markdown support via app-text/discount
mobi Enable mobipocket support via kde-apps/kdegraphics-mobipocket
phonon Enable sound support via media-libs/phonon
plucker Enable Plucker E-Book for Palm OS devices support
qml Install Okular Qml components
share Enable support for a share menu using kde-frameworks/purpose
speech Enable text-to-speech support

pimcommon

designer Build plugins for dev-qt/designer

spectacle

share Enable support for a share menu using kde-frameworks/purpose

step

qalculate Enable the libqalculate library for unit conversion

thumbnailers

mobi Enable mobipocket thumbnail generation using kde-apps/kdegraphics-mobipocket

umbrello

php Enable PHP import support using dev-util/kdevelop and dev-util/kdevelop-pg-qt

yakuake

absolute-position Use kde-frameworks/kwayland for absolute window positioning in KWin

kde-frameworks

kcompletion

designer Build plugins for dev-qt/designer

kconfig

qml Enable QML/QtQuick support via dev-qt/qtdeclarative

kconfigwidgets

designer Build plugins for dev-qt/designer

kfilemetadata

epub Enable support for reading EPUB ebook metadata
mobi Enable mobipocket support via kde-apps/kdegraphics-mobipocket

kglobalaccel

X Build the kglobalacceld runtime needed for X

kiconthemes

designer Build plugins for dev-qt/designer

kimageformats

eps Support the EPS graphics file format

kinit

caps Capabilities support for improved security and better OOM handling

kio

designer Build plugins for dev-qt/designer
kwallet Enable permanent storage of passwords for kpasswdserver with kde-frameworks/kwallet

kitemmodels

qml Enable QML support via dev-qt/qtdeclarative

kitemviews

designer Build plugins for dev-qt/designer

knewstuff

designer Build plugins for dev-qt/designer
opds Enable support for the Open Publication Distribution System via kde-frameworks/syndication

knotifications

phonon Play notification sounds via media-libs/phonon instead of media-libs/libcanberra
qml Enable QML support via dev-qt/qtdeclarative
speech Enable text-to-speech notification support

knotifyconfig

phonon Play notification sounds via media-libs/phonon instead of media-libs/libcanberra

kplotting

designer Build plugins for dev-qt/designer

krunner

activities Enable search runner for KDE Activities history

ktexteditor

editorconfig Enable support for EditorConfig configuration files

ktextwidgets

designer Build plugins for dev-qt/designer
speech Enable text-to-speech support

kwallet

gpg Support wallets with GnuPG encryption in addition to the default blowfish-encrypted file

kwidgetsaddons

designer Build plugins for dev-qt/designer

kxmlgui

designer Build plugins for dev-qt/designer

networkmanager-qt

teamd Enable Teamd control support

prison

qml Enable QML/QtQuick support via dev-qt/qtdeclarative

purpose

kaccounts Enable support for system-wide defined KAccounts

sonnet

aspell Enable the app-text/aspell spell-checking backend
designer Build plugins for dev-qt/designer
hunspell Enable the app-text/hunspell spell-checking backend
qml Enable QML/QtQuick support via dev-qt/qtdeclarative

kde-misc

kdeconnect

X Enable remote input mousepad plugin using x11-libs/libfakekey
pulseaudio Enable system volume control plugin using media-libs/libpulse
telephony Enable telephony plugin using kde-frameworks/modemmanager-qt

kio-gdrive

share Enable support for a share menu using kde-frameworks/purpose

tellico

bibtex Add support for bibtex importing using btparse from dev-perl/Text-BibTeX
discid Add support for reading disc IDs from audio CDs
yaz Add support for searching Z39.50 databases

kde-plasma

discover

firmware Enable support for firmware upgrades using sys-apps/fwupd
flatpak Enable support for flatpak repositories using sys-apps/flatpak
snap Enable support for snap packages using app-containers/snapd
webengine Enable webflow support using dev-qt/qtwebview and dev-qt/qtwebengine instead of default URL handler

drkonqi

systemd Enable Coredumpd integration

kde-cli-tools

kdesu Build graphical frontend for kde-frameworks/kdesu

kdeplasma-addons

alternate-calendar Support alternate calendar systems (currently Chinese or Indian) via dev-libs/icu
networkmanager Disable wallpaper update when using metered connections
share Enable applet for quickly sharing data to a variety of sources
webengine Enable dictionary and web browser applets using dev-qt/qtwebengine

ksystemstats

networkmanager Enable improved backend for Network statistics using kde-frameworks/networkmanager-qt

kwin

lock Enable screen locking via kde-plasma/kscreenlocker
multimedia Enable effect video button in desktop effects KCM

libksysguard

designer Build plugins for dev-qt/designer
webengine Enable display of detailed memory information using dev-qt/qtwebengine.

plasma-desktop

ibus Use ibus input method via app-i18n/ibus
kaccounts Build the OpenDesktop integration plugin
scim Enable applets that use app-i18n/scim

plasma-firewall

firewalld Build net-firewall/firewalld backend
ufw Build net-firewall/ufw backend

plasma-meta

browser-integration Enable integration with Chrome/Firefox with browser extensions
colord Enable kde-plasma/kwin color management via x11-misc/colord
crash-handler Pull in kde-plasma/drkonqi for assisted upstream crash reports
crypt Pull in kde-plasma/plasma-vault for encrypted vaults integration
desktop-portal Enable sys-apps/xdg-desktop-portal backend implementation for Plasma
discover Pull in resources management GUI; a centralised GHNS alternative and optional sys-apps/fwupd frontend
display-manager Pull in a graphical display manager
firewall Pull in kde-plasma/plasma-firewall for system firewall administration
flatpak Pull in kde-plasma/flatpak-kcm for flatpak permissions administration
grub Pull in Breeze theme for sys-boot/grub
gtk Enable Breeze widget style and system settings module for GTK+
kwallet Enable support for KWallet auto-unlocking via kde-plasma/kwallet-pam
legacy-systray Add support for legacy applications using kde-plasma/xembed-sni-proxy
plymouth Pull in Breeze theme for sys-boot/plymouth
pulseaudio Install Plasma applet for PulseAudio volume management
sddm Pull in the x11-misc/sddm display manager and system settings module
sdk Pull in kde-plasma/plasma-sdk for Plasma development
smart Pull in kde-plasma/plasma-disks for disk health monitoring
thunderbolt Pull in kde-plasma/plasma-thunderbolt control center module
wallpapers Install wallpapers for the Plasma Workspace

plasma-nm

openconnect Build support for the OpenConnect VPN client
teamd Enable Teamd control support

plasma-welcome

discover Pull in resources management GUI; a centralised GHNS alternative and optional sys-apps/fwupd frontend
kaccounts Build the OpenDesktop integration plugin

plasma-workspace

appstream Enable AppStream software metadata support
geolocation Enables dataengine providing location information
policykit Enable locale generation and Users KCM using sys-auth/polkit and sys-apps/accountsservice
screencast Enable screencast portal using kde-plasma/kpipewire
telemetry Enable User Feedback control module for kde-plasma/systemsettings
wallpaper-metadata Show metadata for image wallpaper plugin using kde-apps/libkexiv2

powerdevil

brightness-control Enable screen brightness control using app-misc/ddcutil
wireless Enable wireless energy saving actions via kde-frameworks/bluez-qt and kde-frameworks/networkmanager-qt

lxqt-base

liblxqt

backlight Enable backlight control features.

lxqt-config

monitor Build monitor settings tool
touchpad Build touchpad settings tool

lxqt-meta

about Install lxqt-base/lxqt-about
admin Install lxqt-base/lxqt-admin
archiver Install app-arch/lxqt-archiver
desktop-portal Enable the LXQt sys-apps/xdg-desktop-portal backend implementation
display-manager Install a graphical display manager
filemanager Install x11-misc/pcmanfm-qtfile manager
lximage Install media-gfx/lximage-qtimage viewer
minimal Do not install x11-wm/openboxwindow manager
nls Install dev-qt/qttranslations to better support different locales
powermanagement Install lxqt-base/lxqt-powermanagement package
processviewer Install x11-misc/qps package
screenshot Install x11-misc/screengrab package
sddm Install x11-misc/sddm display manager
ssh-askpass Install lxqt-base/lxqt-openssh-askpass user password prompt tool
sudo Install lxqt-base/lxqt-sudo
terminal Install x11-terms/qterminal package
trash Install gnome-base/gvfs to enable 'trash' functionality in x11-misc/pcmanfm-qt

lxqt-panel

colorpicker Build colorpicker plugin
cpuload Build cpuload plugin
desktopswitch Build desktopswitch plugin
directorymenu Build directorymenu plugin
dom Build dom plugin
kbindicator Build kbindicator plugin
mainmenu Build mainmenu plugin
mount Build mount plugin
networkmonitor Build networkmonitor plugin
quicklaunch Build quicklaunch plugin
showdesktop Build showdesktop plugin
spacer Build spacer plugin
statusnotifier Build statusnotifier plugin
sysstat Build sysstat plugin
taskbar Build taskbar plugin
tray Build tray plugin
volume Build volume plugin
worldclock Build worldclock plugin

mail-client

aerc

notmuch Enable support for net-mail/notmuch

alot

doc Install user manual and API documentation

alpine

chappa enhance Alpine by applying Eduardo Chappa's patches
onlyalpine installs only the alpine binary, so it does not collied with pico and/or pine
passfile Adds support for caching passwords into a file between sessions
smime Enable support for S/MIME

balsa

rubrica Adds support for rubrica addressbook
systray Enable System Tray Icon support

claws-mail

archive Enable archiving plugin
bogofilter Build mail-filter/bogofilter plugin
gdata Enable plugin for access to Google data providers
libcanberra Enable sound notification in connection with USE=notification
libnotify Enable notification on the desktop in connection with USE=notification
litehtml Enable dev-libs/gumbo html viewer plugin
notification Notification for new mail in different way, see also USE flags libcanberra, libindicate and libnotify
oauth Enable OAuth2 authentication support
pgp Enable PGP support
sieve Build plugin for sieve filter support
smime Build plugin for S/MIME support
spam-report Enable plugin for spam reporting to various services
spamassassin Build mail-filter/spamassassin plugin

evolution

archive Enable archives support in attachments via app-arch/gnome-autoar
bogofilter Build mail-filter/bogofilter plugin
geolocation Enable support for displaying contacts on a map inside evolution using media-libs/libchamplain
highlight Enable text highlighting plugin
ldap Enable support for fetching contacts from an LDAP or Active Directory server using net-nds/openldap
spamassassin Build mail-filter/spamassassin plugin
weather Enable optional weather calendar support
ytnef Enable optional TNEF attachments parser support using net-mail/ytnef

geary

ytnef Enable optional TNEF attachments parser support using net-mail/ytnef

mutt

autocrypt Enable autocrypt.org support
berkdb Enable sys-libs/db database backend for header caching
gdbm Enable sys-libs/gdbm database backend for header caching
gpgme Build gpgme backend to support S/MIME, PGP/MIME and traditional/inline PGP
gsasl Use GNU SASL via virtual/gsasl instead of Cyrus SASL (requires USE=sasl)
hcache Enable header cache, one database backend needs to be enabled
lmdb Enable dev-db/lmdb database backend for header caching
pgp-classic Build classic_pgp backend to support PGP/MIME and traditional/inline PGP
pop Enable support for POP3 mailboxes
smime-classic Build classic_smime backend to support S/MIME
smtp Enable support for direct SMTP delivery
tokyocabinet Enable dev-db/tokyocabinet database backend for header caching

neomutt

asan Enable Address sanitizer for debugging
autocrypt Enable autocrypt.org support
berkdb Enable BDB (Berkley DB) backend for header caching
gdbm Enable GDBM (GNU dbm) backend for header caching
gpgme Build gpgme backend to support S/MIME, PGP/MIME and traditional/inline PGP
kyotocabinet Enable Kyoto Cabinet database backend for header caching
lmdb Enable LMDB (Lightning Memory-Mapped Database) backend for header caching
lz4 Add lz4 support for header cache compression
notmuch Enable support for net-mail/notmuch
pgp-classic Build classic-pgp backend to support PGP/MIME and traditional/inline PGP
qdbm Enable QDBM (Quicker Database Manager) database backend for header caching
smime-classic Build classic-smime backend to support S/MIME
tokyocabinet Enable Tokyo Cabinet database backend for header caching
ubsan Enable undefined behavior sanitizer for debugging
zlib Add zlib support for header cache compression
zstd Add zstd support for header cache compression

roundcube

change-password Allow users to change passwords through Roundcube
enigma Add dependencies to support server-side GnuPG signing and/or encryption through the enigma plugin
fileinfo Use the dev-lang/php fileinfo extension to guess the mime_type of attachments
ldap Add dependencies to support connecting to an LDAP address book server

s-nail

kerberos If network is enabled, this adds support for GSSAPI login on IMAP through virtual/krb5.
net Enable support for network protocols (POP, IMAP and SMTP). If you only need to send mail with the local Transport Agent, disabling this will get you support for only /usr/sbin/sendmail call.
ssl If network is enabled, this adds support for S/MIME and SSL/TLS-powered protocols through dev-libs/openssl.

thunderbird

clang Use Clang compiler instead of GCC
eme-free Disable EME (DRM plugin) capability at build time
hwaccel Force-enable hardware-accelerated rendering (Mozilla bug 594876)
libproxy Enable libproxy support
lto Enable Link Time Optimization (LTO)
openh264 Use media-libs/openh264 for H.264 support instead of downloading binary blob from Mozilla at runtime
pgo Add support for profile-guided optimization using gcc-4.5, for faster binaries. This option will double the compile time.
pulseaudio Add sound server support via media-libs/libpulse (may be PulseAudio or Pipewire, or apulse if installed)
sndio Enable support for the media-sound/sndio backend
system-av1 Use the system-wide media-libs/dav1d and media-libs/libaom library instead of bundled.
system-harfbuzz Use the system-wide media-libs/harfbuzz and media-gfx/graphite2 instead of bundled.
system-icu Use the system-wide dev-libs/icu instead of bundled.
system-jpeg Use the system-wide media-libs/libjpeg-turbo instead of bundled.
system-libevent Use the system-wide dev-libs/libevent instead of bundled.
system-librnp Use system-wide dev-util/librnp instead of bundled one.
system-libvpx Use the system-wide media-libs/libvpx instead of bundled.
system-png Use the system-wide media-libs/libpng instead of bundled (requires APNG patches)
system-python-libs Use system's python site instead of bundled python libraries
system-webp Use the system-wide media-libs/libwebp instead of bundled.
wifi Enable necko-wifi for NetworkManager integration, and access point MAC address scanning for better precision with opt-in geolocation services

mail-filter

MailScanner

exim Set mail-mta/exim to used MTA
postfix Set mail-mta/postfix to used MTA
spamassassin Enable usage of mail-filter/spamassassin for spam protection

amavisd-new

courier Add courier support
dkim Add DomainKeys Identified Mail support
qmail Add qmail support
razor Add support for mail-filter/razor
rspamd Add support for mail-filter/rspamd extension (HTTP only)
rspamd-https Add support for mail-filter/rspamd extension (both HTTP and HTTPS)
spamassassin Add support for mail-filter/spamassassin

bogofilter

tokyocabinet Enable Tokyo Cabinet database support

dcc

rrdtool Enable net-analyzer/rrdtool interface scripts

libmilter

poll Use poll instead of select

maildrop

authlib Add courier-authlib support
dovecot Add dovecot authentication support
tools Install maildirmake and deliverquota tools
trashquota Count deleted messages as part of the maildir quota

mimedefang

poll Use poll instead of select

opendkim

ldap Enable openldap as a dataset facilitator or keys, determining domains to sign for, and any other dataset that opendkim supports.
lmdb Add support for using dev-db/lmdb
lua Enables control over signature verification, filtering and policy to be controlled by user defined lua scripts.
memcached Add support for using dev-libs/libmemcached
opendbx Use opendbx backend to facilitate dataset driven OpenDKIM configuration options like stats, bodylengthdb, etc. against a wide variety of database types
poll Use poll() instead of select() for the provided asynchronous resolver library.
querycache Add support for query caching (requires 'berkdb' flag)
sasl Used to authenticate to a LDAP server in various ways if required.
stats Add support for statistics (requires 'opendbx' flag)
unbound Use the unbound dnssec library to perform DKIM DNS queries.

opendmarc

reports Install the reports binaries: expire, import, reports, params
spf Use the mail-filter/libspf2 for Sender Policy Framework checking

pyzor

gdbm Enables the Gdbm back-end database engine for pyzord
mysql Enables the MySQL back-end database engine for pyzord through dev-python/mysqlclient.
pyzord Enable the pyzord server daemon
redis Enables the redis back-end database engine for pyzord through dev-python/redis

rspamd

jit Enable PCRE JIT support

spamassassin

cron Install a cron job to update SpamAssassin's rules daily.
qmail Build qmail functionality and docs

mail-mta

courier

fax Enables fax support in the courier mail server
norewrite Prevents courier mail server from mangling virtual user addresses when sending
web Enable the web interface
webmail Enable the webmail interface

exim

arc Adds support for Authenticated Receive Chain (ARC)
dane Adds support for DNS-based Authentication of Named Entities
dcc Adds support for Distributed Checksum Clearinghouse (DCC)
dkim Adds support for DomainKeys Identified Mail (DKIM)
dlfunc Install local_scan.h header to compile separate dlfunc libraries
dmarc Adds support for DMARC
dnsdb Adds support for a DNS search for a record whose domain name is the supplied query
dovecot-sasl Adds support for Dovecot's authentication
dsn Adds support for Delivery Status Notifications (DSN)
exiscan-acl Patch providing support for content scanning
lmtp Adds support for lmtp
mbx Adds support for UW's mbx format
pkcs11 Require pkcs11 support in net-libs/gnutls with USE=gnutls
prdr Adds support for Per-Recipient Data Response
proxy Add support for being behind a proxy, such as HAProxy
redis Adds support for querying dev-db/redis
spf Adds support for Sender Policy Framework
srs Adds support for Sender Rewriting Scheme
srs-alt Use mail-filter/libsrs_alt to implement SRS support
srs-native Use Exim's built-in SRS support to implement SRS support
tdb Use sys-libs/tdb for internal database storage (such as hints database)
tpda Adds support for Transport Post-Delivery Actions

msmtp

daemon Build/install msmtpd MTA daemon
mta Enable this to install as system-wide MTA

netqmail

authcram Enable AUTHCRAM support
gencertdaily Generate SSL certificates daily instead of hourly
highvolume Prepare netqmail for high volume servers
pop3 Include POP3 server

notqmail

gencertdaily Generate SSL certificates daily instead of hourly
highvolume Prepare notqmail for high volume servers
pop3 Include POP3 server

opensmtpd

mta Enable this to install as system-wide MTA

postfix

dovecot-sasl Enable net-mail/dovecot protocol version 1 (server only) SASL implementation
eai Add support for SMTPUTF8
ldap-bind Add support for binding to LDAP backend using dev-libs/cyrus-sasl
lmdb Add support for using dev-db/lmdb for lookup tables
memcached Add support for using net-misc/memcached for lookup tables

qpsmtpd

postfix create user with permissions for proper postfix interaction

ssmtp

mta Install symlinks for sendmail-compatible MTA.

mate-base

caja

mate Install x11-themes/mate-icon-theme which is needed when this package is used in the MATE desktop environment.

mate

base Install base MATE Desktop applications that are recommended for the most common usage; for example, this installs the file manager. Disable this and other USE flags if you want a more minimal MATE Desktop.
extras Install additional MATE Desktop applications that are recommended for extended usage of the MATE Desktop as upstream sees it; for example, this installs MATE Desktop's office related applications. Disable this if you plan to use your own non-MATE Desktop alternatives or a custom mixture of MATE and non-MATE packages.
help Install gnome-extra/yelp to handle in application help menus and documentation browsing
notification Force notification daemon to default to MATE's notification daemon. Enabled by default. Disable if it causes conflicts with other installed desktop environments.
themes Install MATE Desktop's themes; if you use other themes, you can disable this to spare some space and time.

mate-applets

cpupower Enable support for cpu frequency manipulation using sys-power/cpupower
netlink Use dev-libs/libnl

mate-applets-meta

appindicator Pull in mate-extra/mate-indicator-applet for AppIndicator applet
sensors Pull in mate-extra/mate-sensors-applet for hw sensors applet

mate-control-center

accountsservice Add support for AccountsService

mate-session-manager

gles2 Build with support for GLESv2 acceleration sessions

mate-settings-daemon

rfkill build support for rfkill

mate-extra

caja-extensions

cdr Add an extension to burn files to cds using app-cdr/brasero.
gajim Add an extension to support net-im/gajim.
image-converter Add image conversion support.
mail Add an extension to support e-mail functionality.
open-terminal Add an extension to support an open terminal.
pidgin Add an extension to support net-im/pidgin
share Add an extension to support sharing files.
wallpaper Add an extension to support setting an image as the current wallpaper

mate-polkit

accountsservice Support extraction of data from AccountsService

mate-power-manager

applet Enable building of the MATE applet.

mate-system-monitor

wnck Enable experimental support using x11-libs/libwnck.

mate-utils

applet Enable the mate dictionary applet

media-fonts

corefonts

tahoma Also install the Tahoma font. Due to the lack of a free bold variant, this may render badly. See bug 184790.

culmus

ancient Install ancient semitic scripts
fancy Install fancy fonts
fontforge Use media-gfx/fontforge to build fonts from source
taamey Install taamey fonts

dejavu

fontforge Use media-gfx/fontforge to build fonts from source

essays1743

otf Install the OpenType version of the font
ttf Install the TrueType version of the font

fira-mono

otf Install the OpenType version of the font
ttf Install the TrueType version of the font

fira-sans

otf Install the OpenType version of the font
ttf Install the TrueType version of the font

fontawesome

otf Install the OpenType version of the font
ttf Install the TrueType version of the font

fonts-meta

emoji Install a font supporting emojis
latin Install additional latin fonts
ms Install (free) fonts for the "ms" preset

ibm-plex

otf Install OTF fonts
ttf Install TTF fonts

intlfonts

bdf Install BDF fonts in addition to PCF

iosevka

iosevka Install the classic Iosevka font.
iosevka-aile Install Iosevka Aile, a quasi-proportional sans-serif font.
iosevka-curly Install Iosevka Curly, a curlier variant of Iosevka.
iosevka-curly-slab Install Iosevka Curly Slab, the curly font, with slab-serifs.
iosevka-etoile Install Iosevka Etoile, a quasi-proportional slab-serif font.
iosevka-slab Install Iosevka Slab, a monospace slab-serif font.
iosevka-ss01 Install Iosevka SS01, an Iosevka variant made in the style of Andale Mono.
iosevka-ss02 Install Iosevka SS02, an Iosevka variant made in the style of Anonymous Pro Style.
iosevka-ss03 Install Iosevka SS03, an Iosevka variant made in the style of Consolas.
iosevka-ss04 Install Iosevka SS04, an Iosevka variant made in the style of Menlo.
iosevka-ss05 Install Iosevka SS05, an Iosevka variant made in the style of Fira Mono.
iosevka-ss06 Install Iosevka SS06, an Iosevka variant made in the style of Liberation Mono.
iosevka-ss07 Install Iosevka SS07, an Iosevka variant made in the style of Monaco.
iosevka-ss08 Install Iosevka SS08, an Iosevka variant made in the style of Pragmata Pro.
iosevka-ss09 Install Iosevka SS09, an Iosevka variant made in the style of Source Code Pro.
iosevka-ss10 Install Iosevka SS10, an Iosevka variant made in the style of Envy Code R.
iosevka-ss11 Install Iosevka SS11, an Iosevka variant made in the style of X Windows Fixed.
iosevka-ss12 Install Iosevka SS12, an Iosevka variant made in the style of Ubuntu Mono.
iosevka-ss13 Install Iosevka SS13, an Iosevka variant made in the style of Lucida.
iosevka-ss14 Install Iosevka SS14, an Iosevka variant made in the style of JetBrains Mono.
iosevka-ss15 Install Iosevka SS15, an Iosevka variant made in the style of IBM Plex Mono.
iosevka-ss16 Install Iosevka SS16, an Iosevka variant made in the style of PT Mono.
iosevka-ss17 Install Iosevka SS17, an Iosevka variant made in the style of Recursive Mono.
iosevka-ss18 Install Iosevka SS18, an Iosevka variant made in the style of Input Mono.

liberation-fonts

fontforge Use media-gfx/fontforge to build fonts from source

montecarlo

bdf Install BDF fonts in addition to PCF

mplus-outline-fonts

ipafont Generates new fonts merged with media-fonts/ja-ipafonts

noto

extra Install full upstream font set including condensed, semi-bold, extra-light variants

noto-emoji

icons Install Noto Emoji icon theme

sil-charis

compact Use more compactly spaced font

terminus-font

a-like-o Changes view of letter 'a' - a looks like o (see homepage)
center-tilde Place the '~' character vertically centered on the line instead of to the top.
distinct-l ll2 variant with more distinctive l (lowercase L)
otf Install Open Type Font (OTF) (required for HarfBuzz backend)
pcf-8bit Install Portable Compiled Font (PCF) (X11 bitmap fonts), 8-bit encodings
pcf-unicode Install Portable Compiled Font (PCF) (X11 bitmap fonts), Unicode encodings
psf Install PC Screen Font (PSF) with unicode data (for linux console)
quote Changes view of quotes: symmetric ` and ' instead of asymmetric one (see homepage)
ru-dv Changes view of Russian letters 'de' and 've' (see homepage)
ru-g Changes view of Russian letter 'ge' (see homepage)
ru-i Changes view of Russian letter 'i' - not like Latin u, but like "mirrored" N (see homepage)
ru-k Changes view of Russian letter 'k' (see homepage)

unifont

fontforge Use media-gfx/fontforge to build fonts from source
utils Install unifont utilities

vollkorn

otf Install the OpenType version of the font
ttf Install the TrueType version of the font

media-gfx

ahoviewer

plugins Build plugin support for now, in future pull additional plugins
rar Rar archive support
zip Zip archive support

album

plugins Install optional plugins
themes Install optional themes

alembic

hdf5 Add support sci-libs/hdf5
test Build and run the test-suite

asymptote

boehm-gc Enables using the Boehm-Demers-Weiser conservative garbage collector
context Enables support for ConTeXt format (dev-texlive/texlive-context)
curl Enables running remote programs via net-misc/curl
lsp Enables Language Server Protocol
offscreen Enables off-screen rendering
sigsegv Enables using dev-libs/libsigsegv

blender

alembic Add support for Alembic through media-gfx/alembic.
bullet Enable Bullet (Physics Engine).
collada Add support for Collada interchange format through media-libs/opencollada.
color-management Enable color management via media-libs/opencolorio.
cuda Build cycles renderer with nVidia CUDA support.
cycles Build cycles renderer (requires media-libs/openimageio and dev-libs/boost).
cycles-bin-kernels Precompile the cycles render kernels for the CUDA/HIP/OneAPI backends, if they are enabled, at compile time. This makes it so that the user doesn't have to wait for the kernels to compile when they are used for the first time in Blender. If this option is not on, they will be built as needed at runtime.
dds Adds DDS textures support to Blender.
embree Use embree to accelerate certain areas of the Cycles render engine.
fluid Adds fluid simulation support via the built-in Mantaflow library.
headless Build without graphical support (renderfarm, server mode only).
hip Build cycles renderer with AMD HIP support.
nanovdb Enable nanoVDB support in Cycles. Uses less memory than regular openVDB when rendering.
ndof Enable NDOF input devices (SpaceNavigator and friends).
oidn Enable OpenImageDenoiser Support
openimageio Enable OpenImageIO Support
openpgl Enable path guiding support in Cycles
opensubdiv Add rendering support form OpenSubdiv from Dreamworks Animation through media-libs/opensubdiv.
openvdb Enable openvdb for volumetric processing, like the voxel remesher. Also enables volumetric GPU preview rendering for Nvidia cards.
optix Add support for NVIDIA's OptiX Raytracing Engine.
osl Add support for OpenShadingLanguage scripting.
potrace Add support for converting bitmaps into Grease pencil line using the potrace library.
pugixml Enable PugiXML support (Used for OpenImageIO, Grease Pencil SVG export)
tbb Use threading building blocks library from dev-cpp/tbb.

chafa

tools Build command-line tools

darktable

flickr Add support for uploading photos to flickr
gamepad Support using game controllers as input devices
geolocation Enable geotagging support
gmic Use the G'MIC image-processing framework (media-gfx/gmic), e.g. to support Colour LUTs compressed using their compression scheme
kwallet Enable encrypted storage of passwords with kde-frameworks/kwallet
lto Enable link-time optimisations in the RawSpeed library
midi Support using MIDI input devices such as Behringer X-Touch Mini, Arturia Beatstep or Korg nanoKONTROL2, as input devices
opencl Enable opencl support
tools Install tools for generating base curves and noise profiles

digikam

addressbook Enable akonadi contact integration
imagemagick Enable support for additional image formats such as XCF, FITS, HEIC etc.
lensfun Enable support for media-libs/lensfun
marble Enable support for geolocation using kde-apps/marble
panorama Build the panorama plugin which requires media-gfx/hugin
semantic-desktop Enable kde-frameworks/kfilemetadata support

eog-plugins

map Enable world map display using media-libs/libchamplain

eom

imagemagick Use media-gfx/imagemagick as an external backend for the thumbnailer

exact-image

swig Adds Swig support dev-lang/swig

exiv2

bmff Add support for the ISOBMFF format
webready Support reading metadata over the internet

fbida

X Install the Motif based image viewer "ida"
fbcon Install the framebuffer image viewer "fbi"
ghostscript Install the framebuffer ghostscript viewer "fbgs"

fontforge

truetype-debugger Enable truetype debugger in fontforge
woff2 Enable support for WOFF2 format

fotowall

webcam Enable webcam support

freecad

addonmgr Build the addon manager module for automatic handling of 3rd party addons
cloud Build the Cloud workbench, to access cloud providers (mostly Amazon S3).
designer Build and install the Qt designer plugin, so the FreeCAD widgets can be used from within designer.
fem Build the FEM module and workbench which provides Finite Element Analysis (FEA) workflows
gui Build FreeCAD with a Qt based GUI. If built without setting this USE flag, FreeCAD can be used in a headless mode, for server-side instances. The Python modules are available, without their GUI parts though, if this is unset.
idf Build the IDF module to provide file exchange capabilities with IDF files
image Build the image module and workbench for working with bitmap images
inspection Build the inspection workbench which gives you specific tools for examination of shapes (experimental)
material Build the material module and workbench to work with materials
netgen Build support for the netgen mesher through media-gfx/netgen.
openscad Build the OpenSCAD module for interoperability with OpenSCAD and repairing Constructive Solid Geometry (CSG) history
part-design Build the part design module and workbench for build part shapes from sketches
path Build the path module and workbench to procude G-Code instructions for CNC
pcl Use external sci-libs/pcl for point clouds support.
points Build the points module and workbench for working with point clouds
raytracing Build the raytracing module and workbench for raytracing and rendering
robot Build the robot module and workbench for studying robot movements
show Build the show module, a helper module for visibility automation
surface Build the surface module and workbench
techdraw Build the techdraw module and workbench, a more advanced and feature-rich successor of the drawing workbench
tux Build the Tux module

geeqie

ffmpegthumbnailer Enable video thumbnail support with media-video/ffmpegthumbnailer
map Enable items GPS map display

gimp

vector-icons Enable support for vector icons (experimental)

gmic

cli Build CLI interface
opencv Enable support for webcams using the OpenCV library

graphicsmagick

dynamic-loading Compile graphicsmagick with dynamically loadable modules
fpx Enable FlashPix support with media-libs/libfpx
q16 Set storage quantum size to 16 (~2*memory)
q32 Set storage quantum size to 32 (~5*memory)

graphviz

X Builds dotty, lneato, unflatten, vimdot, builds plugin -Txlib, and enables support for x11 in various other modules (needs cairo)
devil Enables DevIL output plugin -Tdevil
gtk2 Enables gtk+ output plugin -Tgtk (needs cairo)
gts Enables support for GNU Triangulated Surface Library (required for sfdp to work)
lasi Enables PostScript output via media-libs/lasi, for plugin -Tlasi (needs cairo)

gthumb

slideshow Enable slideshow plugin

hugin

sift automatically align images with media-gfx/autopano-sift-C

imagemagick

corefonts Use media-fonts/corefonts which is required by some commands
fpx Enable media-libs/libfpx support
hdri Enable High Dynamic Range Images formats
lqr Enable experimental liquid rescale support using media-libs/liblqr
opencl Enable OpenCL support
pango Enable Pango support using x11-libs/pango
q32 Set quantum depth value to 32
q8 Set quantum depth value to 8

imv

freeimage Use media-libs/freeimage for additional image support

inkscape

cdr Enable support for CorelDRAW files via media-libs/libcdr
dia Enable DIA flow chart import via app-office/dia
inkjar Enable support for OpenOffice.org SVG jar files
sourceview Enable syntax highlighting support via x11-libs/gtksourceview
svg2 Enable support for new SVG2 features
visio Enable support for Microsoft Visio diagrams via media-libs/libvisio
wpg Enable support for WordPerfect graphics via app-text/libwpg

iscan-plugin-gt-f500

minimal Install the firmware only, and not the plugin.

kphotoalbum

map Enable map display support using kde-apps/marble
phonon Enable media-libs/phonon video backend (known to crash on some video formats)
share Enable support for a share menu using kde-frameworks/purpose
vlc Enable media-video/vlc video backend (recommended for X11)

krita

color-management Enable color management via media-libs/opencolorio
mypaint-brush-engine Enable MyPaint brush engine support media-libs/libmypaint
qtmedia Enable sound support for animations via dev-qt/qtmultimedia

librecad

tools Build additional tool programs: tff2lff

luminance-hdr

fits Enable support for the FITS format

mandelbulber

opencl Enable GPU rendering support using OpenCL

meshlab

double-precision Use double type instead of float type for scalars

netgen

logging Enable logging through dev-libs/spdlog
opencascade Enable OpenCASCADE support

nomacs

opencv Build support for media-libs/opencv
plugins Build officially support plugins

openclipart

gzip Compresses clip art using gzip

openscad

egl Build using EGL instead of GLX
experimental Enable experimental features
gamepad Add support for gamepads through dev-qt/qtgamepad
gui Enable or disable building of the GUI
hidapi Build in support for HID-Class devices using dev-libs/hidapi
mimalloc Build using dev-libs/mimalloc as memory allocator
spacenav Add support for space navigator devices through dev-libs/libspnav

openvdb

abi10-compat Disables newer features to maintain compatibility with ABI10
abi8-compat Disables newer features to maintain compatibility with ABI8
abi9-compat Disables newer features to maintain compatibility with ABI9
ax Build the OpenVDB AX module to perform custom manipulation of OpenVDB data via an expression language: AX
blosc Allow using blosc compression via dev-libs/c-blosc
cuda Enable support for CUDA in NanoVDB
nanovdb A lightweight, header only, and GPU friendly version of VDB
numpy Build pyopenvdb with support for dev-python/numpy
utils Build utility binaries

photoqt

devil Support additional image formats using media-libs/devil
freeimage Support additional image formats using media-libs/freeimage
mpv Support for video files using media-video/mpv

potrace

metric default to a4 paper size and metric measurement

povray

io-restrictions POV-Ray's mechanism for control of I/O operations

pqiv

archive Enable support for images in archives and cbX comic book files

pstoedit

emf Enable media-libs/libemf support
pptx Enable support for generating PowerPoint pptx files

qimgv

opencv Enable HQ scaling via media-libs/opencv
video Add support for gif/webm playback via libmpv

qrencode

png Enable PNG output support in qrencode tool

renderdoc

pyside2 Expose the QRenderdoc UI to Python scripting to allow for customisation
qt5 Build and install the qrenderdoc GUI

shotwell

opencv Enable face detection via media-libs/opencv

skanpage

ocr Enable support for Optical Character Recognition via app-text/tesseract

solvespace

system-mimalloc Use system dev-libs/mimalloc instead of vendored library

ueberzugpp

opencv Use media-libs/opencv for additional image formats and OpenCL accelerated scaling
wayland Enable wayland support (proper window positioning is only supported with some compositors)
xcb-errors Use x11-libs/xcb-util-errors for better error reporting with X

xpaint

pgf Support for loading PGF images

xsane

ocr Enable support for Optical Character Recognition reader

yafaray

fastmath Enable mathematic approximations to make code faster
fasttrig Enable trigonometric approximations to make code faster
opencv Add support for media-libs/opencv image processing.

media-libs

a52dec

djbfft Prefer D.J. Bernstein's library for fourier transforms

allegro

dumb Enable media-libs/dumb module library support
physfs Enable physfs support
vga Enables the VGA graphics driver

alsa-lib

alisp Enable support for ALISP (ALSA LISP) interpreter for advanced features.

alure

dumb Enable media-libs/dumb module library support
fluidsynth Enables Fluidsynth MIDI software synthesis

assimp

samples Build viewer library

aubio

double-precision Compile in double precision mode.

avidemux-core

system-ffmpeg Use the ffmpeg provided by the system.

avidemux-plugins

aften Enable A/52 (AC-3) audio encoder support.
amr Enable Adaptive Multi-Rate format support via media-libs/opencore-amr.
dcaenc Enable DTS Coherent Acoustics audio encoder support via media-sound/dcaenc.
fdk Adds support for encoding AAC using media-libs/fdk-aac.
fribidi Enable unicode bidirectional algorithm support via dev-libs/fribidi.
twolame Enable TwoLAME support via media-sound/twolame, an optimised MPEG Audio Layer 2 (MP2) encoder.
vpx Enable WebM VP8 Codec SDK support via media-libs/libvpx.
x265 Enables HEVC support with media-libs/x265.

cal3d

16bit-indices Enables use of 16bit indices

chromaprint

tools Build and install fpcalc and fpcollect tools

clutter

egl Enable EGL backend.
gtk Use gdk-pixbuf from x11-libs/gtk+ as image rendering backend

cogl

gles2 Enable OpenGL ES 2.0 support
kms Enable KMS support.
pango Build cogl-pango library for x11-libs/pango integration

coin

exceptions Compile with C++ exceptions
qthelp Build API documentation in QtHelp format

cubeb

rust Use the newer rust-based audio backends if available
sndio Enable support for the media-sound/sndio backend

dav1d

10bit Add support for building 10-bit and 12-bit AV1.
8bit Add support for decoding 8-bit AV1.
asm Enable custom assembly for faster decoding.
xxhash Enable dev-libs/xxhash support for hashing muxer

devil

allegro Add support for Allegro

dumb

allegro Add support for Allegro 4

embree

compact-polys Enables double indexed poly layout.
ispc Build Embree with support for ISPC applications.
raymask Enables ray mask support.
ssp When enabled, Embree compiles with stack protection against return address overrides. Stack protection will wield a minor performance decrease in return for higher security.
tbb Use TBB instead of the built-in Embree tasking system.
tutorial Enable to build Embree tutorials programs.

esdl

image Enable image support

faad2

digitalradio Digital Radio Mondiale (warning: disables other decoders)

fcft

harfbuzz Use media-libs/harfbuzz for grapheme and run shaping
libutf8proc Use media-libs/harfbuzz and dev-libs/libutf8proc for run shaping

flickcurl

raptor Use media-libs/raptor for proper RDF serializing

freetype

adobe-cff Use Adobe CFF as default font-renderer
bzip2 Support bzip2 compressed PCF fonts.
cleartype-hinting Bytecode hinting mode for TrueType fonts that activates subpixel hinting (a.k.a. ClearType hinting) by default
fontforge Install internal headers required for TrueType debugger in media-gfx/fontforge (built with USE=truetype-debugger)
harfbuzz Use media-libs/harfbuzz for auto-hinting OpenType fonts. WARNING: may trigger circular dependencies!
infinality Enable infinality options for improved LCD filtering
utils Install utilities and examples from ft2demos

freeverb3

forcefpu Disable assembly code
plugdouble Build plugins in double precision mode (default is float)

ganv

fdgl Use experimental force-directed graph layout

gegl

lensfun Enable support for media-libs/lensfun.
sdl2 Add support for Simple Direct Layer 2.0 (media-libs/libsdl2)
umfpack Enable sparse solving via sci-libs/umfpack.

glew

egl-only Enable EGL support and disable X11 support

glfw

wayland-only Enable wayland support and disable X11 support

gmmlib

custom-cflags Do not override user CFLAGS like -march, -msse and similar with lib defaults. Not tested by upstream.

grilo

playlist Enable support for playlists through dev-libs/totem-pl-parser

gst-plugins-bad

bzip2 Enable bzip2 encoder/decoder plugin
egl Enable EGL support
gles2 Enable GLES2 support
qsv Enable Intel Quick Sync Video using the media-libs/oneVPL dispatcher

gst-plugins-base

X Enable ximagesink and xvimagesink plugins; build GLX platform support if USE=opengl is enabled; build x11 windowing system support if USE=egl is enabled
egl Enable EGL platform support
gbm Enable Graphics Buffer Manager based EGL windowing system support (requires egl and at least one of gles or opengl)
gles2 Enable OpenGL library and plugin via GLESv2 API (requires egl)
ivorbis Enable integer based vorbis decoder
opengl Enable OpenGL library and plugin via desktop OpenGL API
pango Enable pango GStreamer plugin
wayland Enable Wayland EGL windowing system support (requires egl and at least one of gles2 or opengl)

gstreamer

orc Disable some PaX memory protections to allow plugins that use dev-lang/orc for runtime optimization to be used on hardened PaX systems
unwind Enable sys-libs/libunwind usage for better backtrace support in leaks tracer module

harfbuzz

experimental Enable experimental APIs
glib Enable dev-libs/glib unicode functions
graphite Enable media-gfx/graphite2 complementary shaper

imlib2

X Use the X window system
apidoc Provide doxygen generated API docs
bzip2 Bzip2 loader support
eps Eps image loader support
filters Build filter functions (blur, sharpen, etc)
gif Gif image loader support
heif Heif and Avif image loader support
jpeg Jpeg image loader support
jpegxl Jxl image loader support
mp3 ID3 loader support
packing Enable structure packing. This will reduce memory footprint at the cost of unaligned memory access
png PNG image loader support
shm Use MIT shared memory support for X image transfer
text Build text (TrueType font) functions
tiff TIFF image loader support
webp WEBP image loader support
zlib Zlib loader support

intel-mediasdk

tools Build analyse and inspect tools

jasper

heif Enable experimental support for HEIF/HEIC, unsupported by upstream

leptonica

utils Install command-line utilities

lib3mf

system-act Use system-provided dev-go/act as code generator instead of package provided binaries. This flag will be removed after some time used for testing!

libafterimage

shaping Use MIT shaped X windows extention.
shm Use MIT shared memory extention for X image transfer.

libao

sndio Add support for media-sound/sndio

libavif

aom Enable support for the AOM codec encoding and decoding
dav1d Enable support for the dav1d codec decoding
extras Build extra apps (avifenc, avifdec) and test files
gdk-pixbuf Build a gdk-pixbuf loader
rav1e Enable support for the rav1e codec encoding
svt-av1 Enable support for the SVT-AV1 encoder

libbdplus

aacs Add support for decryption of AACS

libbluray

aacs Add support for decryption of AACS
bdplus Use media-libs/libbdplus for BD+ decryption
java Add support for BD-J
utils Install command-line utilities and examples

libcanberra

alsa Enables ALSA sound driver.
gstreamer Enables gstreamer sound driver. Not useful when alsa or pulseaudio is available.
gtk2 Enables building of gtk+ helper library, gtk+ runtime sound effects and the canberra-gtk-play utility. To enable the gtk+ sound effects add canberra-gtk-module to the colon separated list of modules in the GTK_MODULES environment variable.
gtk3 Enables building of gtk+3 helper library, gtk+3 runtime sound effects and the canberra-gtk-play utility. To enable the gtk+3 sound effects add canberra-gtk-module to the colon separated list of modules in the GTK_MODULES environment variable.
pulseaudio Enables PulseAudio sound driver that should be able to support positional event sounds. This is the preferred choice for best sound events experience and picked by default if compiled in and possible to use at runtime.
sound Install x11-themes/sound-theme-freedesktop to get sounds on Gnome and Xfce.
tdb Enables Trivial Database support for caching purposes.

libde265

dec265 Enable build of dec265 example program
enc265 Enable build of enc265 tool
sdl Enable video output of dec265 example program with media-libs/libsdl
tools Enable installation of varous binary tools

libepoxy

egl Enable EGL support.

libffado

test-programs Install standalone test programs

libggi

3dfx Enables support for Voodoo chipsets, also called 3DFX and TDFX
vis Enables sparc vis support for libggi

libgphoto2

serial Enable serial port support

libgpod

gtk Enable ArtworkDB support

libheif

aom Use media-libs/libaom for AVIF encoding/decoding
gdk-pixbuf Enable x11-libs/gdk-pixbuf plugin
go Enable building dev-lang/go code/examples
rav1e Use media-video/rav1e for AVIF encoding
x265 Use media-libs/x265 for HEIF encoding

libjxl

gdk-pixbuf Build a gdk-pixbuf loader

liblastfm

fingerprint Build the lastfm-fingerprint library

libmp4v2

utils Install command-line utilities

libmpg123

int-quality Use rounding instead of fast truncation for integer output, where possible

libmypaint

gegl Add support for media-libs/gegl

libopenglrecorder

openh264 Enable H.264 support using media-libs/openh264
vpx Enable VP8/VP9 codec support via media-libs/libvpx

libopenshot

babl Enable media-libs/babl support
opencv Enable media-libs/opencv support

libpagemaker

tools Build command line file format conversion tools

libpano13

suitesparse Use Sparse Levenberg Marquardt algorithm instead of dense Levenberg Marquardt algorithm

libplacebo

glslang Use dev-util/glslang to compile GLSL
lcms Add support for color management via media-libs/lcms
shaderc Use media-libs/shaderc to compile GLSL
xxhash Use dev-libs/xxhash to speed up internal hashing

libpng

apng support unofficial APNG (Animated PNG) spec

libprojectm

gles2 Provide support for OpenGL ES 2 and 3

libpulse

asyncns Use libasyncns for asynchronous name resolution.
doc Build the doxygen-described API documentation.
glib Add support to dev-libs/glib-based mainloop for the libpulse client library, to allow using libpulse on glib-based programs.

libsdl

joystick Control joystick support (disable at your own risk)
sound Control audio support (disable at your own risk)
tslib Build with tslib support for touchscreen devices
video Control video support (disable at your own risk)

libsdl2

fcitx4 Enable support for app-i18n/fcitx 4
gles1 include OpenGL ES 1.0 support
gles2 include OpenGL ES 2.0 support
haptic Enable the haptic (force feedback) subsystem
ibus Enable support for app-i18n/ibus
joystick Control joystick support (disable at your own risk)
kms Build the KMSDRM video driver
pipewire Enable support for the media-video/pipewire audio backend
sndio Enable support for the media-sound/sndio backend
sound Control audio support (disable at your own risk)
video Control video support (disable at your own risk)

libshumate

sysprof Enable sysprof-capture support for profiling

libtgvoip

dsp Enable signal processing (echo cancellation, noise suppression, and automatic gain control)

libva-compat

drm Enables VA/DRM API support.
egl Enables EGL support.

libva-intel-driver

hybrid Enable support for hybrid vaapi hardware acceleration on Intel Haswell and newer architectures

libva-intel-media-driver

redistributable Install redistributable media kernel binaries (no source code) files (primarily needed for video encoding support)

libvisio

tools Build conversion tools

libvmaf

embed-models Compile default vmaf models into the library (needs app-editors/vim-core)

libvpx

highbitdepth Enable 10 and 12 bit support for VP9.
postproc Enable additional post processing filters

libwebp

swap-16bit-csp Enable byte swapping for 16 bit colorspace

libzmf

tools Build conversion tools

lilv

tools Build command line utilities

lsp-plugins

lv2 Build lv2 plugins
vst Support LinuxVST plugins

lv2

plugins Enables examples plugins.

lvtk

gtk2 Enable x11-libs/gtk+:2 based GUI support
tools Compile and install ttl2c tool

mesa

d3d9 Enable Direct 3D9 API through Nine state tracker. Can be used together with patched wine.
gles1 Enable GLESv1 support.
gles2 Enable GLESv2 support.
llvm Enable LLVM backend for Gallium3D.
lm-sensors Enable Gallium HUD lm-sensors support.
opencl Enable the Rusticl Gallium OpenCL state tracker.
osmesa Build the Mesa library for off-screen rendering.
proprietary-codecs Enable codecs for patent-encumbered audio and video formats.
vdpau Enable the VDPAU acceleration interface for the Gallium3D Video Layer.
vulkan-overlay Build vulkan-overlay-layer which displays Frames Per Second and other statistics
wayland Enable support for dev-libs/wayland
xa Enable the XA (X Acceleration) API for Gallium3D.
zink Enable the Zink OpenGL-over-Vulkan Gallium driver

mesa-amber

gles1 Enable GLESv1 support.
gles2 Enable GLESv2 support.
wayland Enable support for dev-libs/wayland

mlt

frei0r Build the module for media-plugins/frei0r-plugins
opencv Build motion tracking module using media-libs/opencv
python Build SWIG bindings for Python
rtaudio Builds rtaudio consumer for native audio support on multiple platforms
rubberband Enable audio pitch-shifting using media-libs/rubberband
vidstab Enabled video stabilization with media-libs/vidstab

netpbm

rle Build converters for the RLE format (utah raster toolkit)

noise-suppression-for-voice

lv2 Enable the LV2 plugin
vst Enable the VST plugin
vst3 Enable the VST3 plugin

oneVPL

drm Build with DRM support
experimental Build dispatcher with experimental APIs
tools Build decode/encode/analyse/inspect tools

oneVPL-cpu

experimental Enable experimental API
openh264 Use media-libs/openh264 instead of media-libs/x264

openal

pipewire Enable support for the media-video/pipewire audio backend
sndio Enable support for the media-sound/sndio backend

opencolorio

apps Build the OCIO command line apps

opencv

contrib Install user contributed scripts from opencv_contrib (Experimental!)
contribcvv CVV module requires Qt5
contribdnn DNN module contrib requires tiny dnn
contribfreetype Enable Drawing UTF-8 strings with freetype/harfbuzz
contribhdf HDF module requires sci-libs/hdf5
contribovis Enable Ogre vision module support
contribsfm SFM module requires eigen, gflags, and glog
contribxfeatures2d Enables xfeatures2d and autodownload of samples in contrib
cuda Enable NVIDIA Cuda computations support (Experimental!)
dnnsamples Download dnn caffeemodel samples
download Enable download during cmake configure
eigen Enable usage of dev-cpp/eigen for computations
features2d Enable features2d module
gdal Enable support for sci-libs/gdal library
gflags Use Google's C++ argument parsing library
glog Use Google's C++ loggin library
gtk3 Enable x11-libs/gtk+:3 support
lto Build using Link Time Optimizations (LTO)
opencl Add support for OpenCL
opencvapps Enable compilation with opencvapps
tesseract Use Google's OCR Engine
testprograms Build and install programs for testing OpenCV (performance)
vtk Build new 3D visualization module viz based on sci-libs/vtk

openexr

large-stack Enables code to take advantage of large stack support.
utils Build several binary tools for verifying and manipulating EXR files.

openh264

plugin Install the Gecko Media Plugin (GMP) for use with Mozilla packages
utils Install the CLI encoder and decoder utilities

openimageio

dicom Enable DICOM medical image file support via sci-libs/dcmtk
opencv Enable OpenCV support via media-libs/opencv
openvdb Enable OpenVDB support via media-gfx/openvdb
ptex Enable Ptex texture mapping system file support via media-libs/ptex
qt5 Build iv with Qt5
qt6 Build iv with Qt6
tools Build the command-line tools

opensubdiv

cuda Enable NVIDIA CUDA Toolkit support through dev-util/nvidia-cuda-toolkit
opencl Enable OpenCL support through virtual/opencl
ptex Adds support for faster per-face texture mapping through media-libs/ptex
tbb Enable multithreading with the Intel Threads Building Blocks through dev-cpp/tbb
tutorials Install the tutorials

opus

custom-modes Enable non-Opus modes, e.g. 44.1 kHz and 2^n frames

opusfile

fixed-point Enable fixed-point arithmetic operations
float Enable floating point arithmetic operations
http Enable http connections

osl

partio Use media-libs/partio
qt5 Build the osltoy binary

phonon

designer Install plugin for dev-qt/designer
vlc Install VLC Phonon backend

phonon-gstreamer

network Enable network streaming support via libsoup

portmidi

test-programs Install various example programs

quarter

designer Install plugin for dev-qt/designer
qthelp Build API documentation in QtHelp format

raptor

json Enable support for JSON parsing

raspberrypi-userland-bin

hardfp Use armv6 hardfp ABI

roc-toolkit

tools Install helper tools like roc-conv, roc-recv, roc-send

rubberband

jni Enables building of Java Native Interface library
lv2 Add support for Ladspa V2
programs Builds also executable applications
vamp Enables vamp plugins support (Audio analysing plugins)

sdl-mixer

fluidsynth Use media-sound/fluidsynth for MIDI support
midi basic support for MIDI files
mod basic support for MOD files
playtools Install playwave and playmus tools (useful for testing)
smpeg Use media-libs/smpeg for MP3 support
wav support WAVE files

sdl2-mixer

fluidsynth Use media-sound/fluidsynth for MIDI support
midi basic support for MIDI files
mod basic support for MOD files
playtools Install playwave and playmus tools (useful for testing)
tremor enable OGG Vorbis music via libtremor
wav support WAVE files

sdl2-ttf

harfbuzz Use media-libs/harfbuzz for enhanced font rendering

sdl_audiolib

fluidsynth Enable support for MIDI via media-sound/fluidsynth
mpg123 Enable support for mp3 decoding via media-sound/mpg123
openmpt OpenMPT decoder via media-libs/libopenmpt
soxr Enable SoX Resampler support via media-libs/soxr
wildmidi Enable support for MIDI via media-sound/wildmidi

sge

image enable sdl-image support

spandsp

fixed-point Enable fixed point support

speex

utils Enables speex commandline utilities (speexenc, speexdec).
vbr Enable VBR support.

suil

gtk2 Enable GTK2 based GUI support

svgalib

kernel-helper Build the helper kernel module

tremor

low-accuracy enable 32bit only multiply operations

urt

tools Install tools

vips

archive Enable support for compressed files using app-arch/libarchive
deprecated Enable deprecated components
fits Enable support for the Flexible Image Transport System data format using sci-libs/cfitsio
gsf Enable support for structured files using gnome-extra/libgsf
highway Enable SIMD optimizations using dev-cpp/highway (replaces USE=orc)
imagequant Enable support for Image Quantization using media-gfx/libimagequant
matio Enable support for matlab files using sci-libs/matio
pango Enable support for text rendering using x11-libs/pango

vulkan-loader

layers Include the vulkan layers

waffle

egl Enable EGL support
gbm Enable support for the Generic Buffer Manager (gbm)
wayland Enable Wayland support

x264

interlaced enable interlaced encoding support, this can decrease encoding speed by up to 2%
opencl Add support for OpenCL.
pic disable optimized assembly code that is not PIC friendly

x265

10bit Add support for producing 10bits HEVC.
12bit Add support for producing 12bits HEVC.
numa Build with support for NUMA nodes.
pic Disable optimized assembly code that is not PIC friendly

xine-lib

bluray Enable playback of Blu-ray filesystems using media-libs/libbluray
dav1d Enable support for media-libs/dav1d AV1 decoder
dxr3 Enable support for DXR3 mpeg acceleration cards.
flac Build the media-libs/flac based FLAC demuxer and decoder. This flag is not needed for playing FLAC content, neither standalone nor in Ogg container (OggFLAC), but might have better support for exotic features like 24-bit samples or 96kHz sample rates.
gtk Build the gdkpixbuf-based image decoder plugin.
imagemagick Build the ImageMagick-based image decoder plugin.
mad Build the media-libs/libmad based mp3 decoder. This mp3 decoder has superior support compared to the one coming from FFmpeg that is used as a fallback. If you experience any bad behaviour with mp3 files (skipping, distorted sound) make sure you enabled this USE flag.
mmap Use mmap() function while reading file from local disks. Using mmap() will use more virtual memory space, but leaves to the Kernel the task of caching the file's data. mmap() access should be faster, but might misbehave if the device where the file resides in is removed during playback.
nfs Allow accessing NFS shares via net-fs/libnfs.
sftp Use net-libs/libssh2 to access SFTP servers.
truetype Use media-libs/freetype for font rendering and media-libs/fontconfig for font discovery. Enabling this USE flag will allow OSD (such as subtitles) to use more advanced font and to more easily select which font to use. The support for TrueType fonts in xine-lib is still experimental, and might not be as good looking as the bitmap fonts used with this USE flag disabled.
vdr Build the VDR plugin
vidix Enable support for vidix video output.
vis Adds support for SIMD optimizations for UltraSPARC processors.
vpx Enable VP8 codec support via media-libs/libvpx.
xvmc Enable support for XVideo Motion Compensation (accelerated mpeg playback).

xvid

pic disable optimized assembly code that is not PIC friendly

zita-resampler

tools Install zresample and zretune tools

zmusic

fluidsynth Enable support for MIDI via media-sound/fluidsynth
mpg123 Enable support for MPEG audio playback via media-sound/mpg123

media-plugins

alsa-plugins

arcam_av Enables Arcam AV control plugin
mix Enables upmix and vdownmix plugin
usb_stream Enables usb_stream plugin

audacious-plugins

ampache Support controlling audacious via ampache
bs2b Enable Bauer Bauer stereophonic-to-binaural headphone filter
cue Support CUE sheets using the libcue library
fluidsynth Support FluidSynth as MIDI synth backend
gme Support various gaming console music formats
http Support HTTP streams through neon
openmpt Add support for OpenMPT
pipewire Build the PipeWire output plugin
scrobbler Build with scrobbler/LastFM submission support
sid Build with SID (Commodore 64 Audio) support
soxr Build with SoX Resampler support
speedpitch Enable speed/pitch effects
streamtuner Build the streamtuner plugin

calf

experimental Enable experimental features/plugins
lv2 Add support for Ladspa V2

frei0r-plugins

facedetect Enables building of facedetect plugin, which depends on media-libs/opencv
scale0tilt Enables building of scale0tilt and vectorscope plugins, which depend on media-libs/gavl

gkrellmpc

threads Use separate thread to init connection (unsafe)

grilo-plugins

chromaprint Enable Chromaprint support
daap Enable dmap support through net-libs/libdmapsharing
flickr Enable Flickr support
freebox Build support for viewing TV channels using Freebox
gnome-online-accounts Enable net-libs/gnome-online-accounts support
thetvdb Build support for thetvdb.com
tracker Build support for content discovery using the app-misc/tracker indexer
youtube Build support for YouTube content discovery using dev-libs/libgdata

gst-plugins-gtk

egl Enable EGL platform usage
gles2 Enable gtkglsink OpenGL sink based on GLESv2 API
opengl Enable gtkglsink OpenGL sink based on desktop OpenGL API

gst-plugins-meta

http Enable http streaming via net-libs/libsoup
libvisual Enable visualization effects via media-libs/libvisual
vpx Enables vp8 codec support using libvpx, required to play some HTML5 videos

gst-plugins-vaapi

drm Enable DRM renderer
egl Enable EGL support
gles2 Enable GLESv2 and GLESv3 support

imlib2_loaders

xcf Enable XCF image loader

ir_lv2

tools Build convert4chan tool

vdr-burn

dvdarchive DMH DVD - Archive

vdr-cdplayer

cdparanoia Enable cdparanoia (audio CD ripper) support

vdr-dvbapi

dvbcsa use media-libs/libdvbcsa free implementation of the DVB Common Scrambling Algorithm

vdr-epgsearch

conflictcheckonly install the "conflictcheckonly" vdr-plugin
epgsearchonly install the "epgsearchonly" vdr-plugin
quicksearch install the "quicksearch" vdr-plugin
tre Add support for unlimited fuzzy searching with help of dev-libs/tre library

vdr-streamdev

client Compile the VDR plugin vdr-streamdev-client that can connect a vdr to a remote streamdev-server instance
server Compile the VDR plugin vdr-streamdev-server that allows remote systems to access the vdr using streamdev-specific VTP and HTTP protocol

vdr-vdrmanager

stream Add support for streaming Video to Android client

vdr-weatherng

dxr3 enables lower osd color depth for dxr3 cards

vdr-xineliboutput

bluray Enable BluRay metadata support through media-libs/libbluray
cec Enable CEC support through dev-libs/libcec
vdr Compile the vdr output plugin to use local or remote xine as output
xine Compile the xine input plugin for displaying vdr video and OSD

media-radio

ax25-tools

X Enable some X based configuration tools.

chirp

radioreference pull in optional deps for query of radioreference

direwolf

hamlib Enables support by the Hamlib amateur radio rig control library

fldigi

hamlib Enables support by the Hamlib amateur radio rig control library to get/set frequency and mode of the ham radio in use

tucnak

hamlib Enables support by the Hamlib amateur radio rig control library to get/set frequency and mode of the ham radio

unixcw

ncurses Enables building the curses based morse code tutor program 'cwcp'.

xastir

geotiff Install geotiff support. Allows using USGS DRG topo maps or other types of geotiff mapes/images

media-sound

abcde

aiff Enable support for Audio Interchange File Format (AIFF) output encoding
id3tag Support ID3, ID3v2 tagging of audio files
mac Enable support for Monkey's Audio files
normalize Add support for normalizing audio file volume levels
replaygain Support for Replay Gain metadata, for relative volume adjustment

abcm2ps

pango Use the pango library to render fonts with non-latin characters

alsa-utils

bat install basic audio tester (BAT) util
libsamplerate install utils that use libsamplerate (e.g. alsaloop)
ncurses install utils that use ncurses (e.g. alsamixer)

alsaplayer

id3tag Enables ID3 tagging with id3tag library

amsynth

dssi Enable support for DSSI Soft Synth Interface
lv2 Add support for Ladspa V2
nsm Build support for Non Session Manager
vst Build VST plug-in

apulse

sdk Install PulseAudio headers and pkg-config files. Be aware apulse is not a full PulseAudio replacement by design and some functionality may be missing.

aqualung

ifp Enable support for iRiver iFP portable audio players
lua Enable support for programmable title formatting with dev-lang/lua
mac Enable support for decoding Monkey's Audio files
podcast Enable podcast support
systray Enable system tray support

ardour

phonehome contact ardour.org at startup for new announcements

ario

idle Enable experimental support for MPD's idle command to reduce bandwidth and cpu usage, requires MPD 0.14

asunder

mac Support for creation of Monkey's Audio files (APE)

audacity

audiocom Enable integrated uploading to audio.com
id3tag Enables ID3 tagging with id3tag library
lv2 Add support for Ladspa V2
mpg123 Use media-sound/mpg123 instead of media-libs/libmad for decoding MPEG decoding
portmidi Enable support for MIDI via media-libs/portmidi
portmixer Enable the internal portmixer feature
portsmf Enable support for Portable Standard Midi File Library
sbsms Enables sbsms library support for slower, more accurate pitch and tempo changing
twolame Enables twolame support (MPEG Audio Layer 2 encoder)
vamp Enables vamp plugins support (Audio analysing plugins)
vst Enable VST plugin support

audiotools

cue Enable CUE sheet support
dvda Enable DVD-Audio support
twolame Enable twolame support (MPEG Audio Layer 2 encoder)

bluez-alsa

aptx aptX (HD) over Bluetooth (many Android compatible headphones)
hcitop Enable top-like monitoring tool for HCI
ldac Enable support for AOSP media-libs/libldac dispatcher
mpg123 Enable support for MPEG audio playback via media-sound/mpg123
ofono Enable ofono elephony support

cadence

a2jmidid Enables support for legacy ALSA sequencer applications in JACK MIDI system

cantata

cdio Use dev-libs/libcdio-paranoia for CD support (instead of cdparanoia)
http-server Enable internal HTTP server to play non-MPD files
replaygain Enable ReplayGain support, for relative volume adjustments
streaming Enable playback of MPD HTTP streams using LibVLC (media-video/vlc)

cava

pipewire Enable support for the media-video/pipewire backend
sndio Enable support for the media-sound/sndio backend

clementine

box Enable filesharing via Box.com
dropbox Enable Dropbox support
googledrive Enable Google Drive support
lastfm Use liblastfm for fetching song info, scrobbling and radio streams
moodbar Enable moodbar support
projectm Build with ProjectM visualization
seafile Enable support for seafile: a file sync service
skydrive Enable Skydrive support
wiimote Enable support for Wii remote

cmus

cdio Use libcdio for CD support
discid Enable reading the ID of the inserted CD
elogind Enable MPRIS support via sys-auth/elogind
pidgin Install support script for net-im/pidgin
sndio Add support for media-sound/sndio
systemd Enable MPRIS support via sys-apps/systemd
tremor Use libivorbis from media-libs/tremor instead of media-libs/libvorbis

csound

beats Build the beats score frontend
double-precision Use double-precision floating point for audio samples
dssi Build the DSSI opcodes
portmidi Build the PortMIDI I/O module
samples Install the HRTF datafiles for use with hrtfmove, hrtfmove2, hrtfstat, hrtfearly, and hrtfreverb
utils Build stand-alone executables for utilities that can also be used via `csound -U`

darkice

twolame Build with twolame support

deadbeef

converter File format converter
cover Support for cover art
hotkeys Keyboard shortcuts support
lastfm last.fm/AudioScrobbler protocol support
libretro libretro resampling plugin
libsamplerate Support the Secret Rabbit Code resampler
notify Desktop notifications support
nullout Dummy output driver
pipewire Pipewire output plugin
sc68 Atari ST and Amiga music player
shellexec Define custom shell commands that can be called on tracks
supereq Enable equalizer

denemo

alsa Enable alsa support through media-libs/alsa-lib
aubio Enable media-libs/aubio support
jack Enable jack support through virtual/jack
portaudio Enable support for media-libs/portaudio
portmidi Enable support for the media-libs/portmidi backend
rubberband Enable support for media-libs/rubberband

dir2ogg

mac Add support for decoding Monkey's Audio files
wma Add support for wma files through mplayer

drumstick

fluidsynth Enable support for media-sound/fluidsynth
network Build Network RT backend

easyeffects

calf Enable use of media-plugins/calf for adding various FX
doc Install packages needed to display built-in user documentation
mda-lv2 Enable use of media-plugins/mda-lv2 for the loudness FX
zamaudio Enable use of media-plugins/zam-plugins for the maximizer FX

easytag

nautilus Build gnome-base/nautilus extension

ecasound

lv2 Add support for Ladspa V2
oil Use dev-libs/liboil for inner loop optimizations

elisa

mpris Enable MPRIS support
vlc Use media-video/vlc for output rather than dev-qt/qtmultimedia

exaile

scrobbler Enable audioscrobbler/last.fm support

fapg

xspf Enable support for saving XSPF playlists.

fluidsynth

network enable network support (requires BSD sockets)
pipewire enable media-video/pipewire support

gimmix

cover Enable cover art fetching
lyrics Enable lyric fetching

guitarix

lv2 Build lv2 plugins
nsm Build NSM (Non Session Manager) support
standalone Build standalone application

herrie

http Enable http streaming
xspf Enable support for reading and saving XSPF playlists

hydrogen

archive Use libarchive instead of libtar
portmidi Add portmidi support

jack-audio-connection-kit

pam Add basic realtime configuration via sys-auth/realtime-base

jack-example-tools

jack-net Build jack_net_* example clients
jack-netsource Build jack_netsource for configuring network sources
zalsa Build the zalsa internal client using media-libs/zita-resampler

jack2

classic Enable building of jackd
metadata Enable metadata API
pam Add basic realtime configuration via sys-auth/realtime-base
tools Pull basic tools (e.g. jack_lsp/connect) from media-sound/jack-example-tools

kasts

vlc Enable media-video/vlc backend

kid3

acoustid Build acoustic fingerprinting plugin using media-libs/chromaprint
mpris Enable support for MPRIS2 interface using dev-qt/qtdbus

klick

rubberband Enable rubberband support

lame

frontend Build and install the 'lame' executable frontend to lame libraries.
mp3rtp Build the mp3-to-RTP streaming utility. **UNSUPPORTED**

liblc3

tools Enable extra tools

lilypond

guile2 Enable experimental support for Guile 2

linux-show-player

midi Allow cues to send, or trigger on, MIDI messages
timecode Support the sending of time code of running audio files over ArtNet, for instance to trigger cues in lighting-control software on lighting desks

linuxsampler

lv2 Add support for Ladspa V2
sf2 Add support for SoundFont 2 sound bank files

lmms

fluidsynth Enables Fluidsynth MIDI software synthesis plugin.
libgig Enables GIG player plugin.
soundio Enables libsoundio support.
stk Enables STK Mallet plugin.
vst Enables the VeSTige plugin to run VST plugins through Wine.

mangler

espeak Text to speech engine
g15 Logitech g15 lcd support

mixxx

hid Enable HID controller support
keyfinder Enable musical key detection support via media-libs/libkeyfinder
lv2 Add support for Ladspa V2 via media-libs/lilv
modplug Add libmodplug support
qtkeychain Enable Secure credential storage support via dev-libs/qtkeychain
shout Enable broadcasting support via media-libs/libshout

moc

cache Enable tags caching support
sid Build with SID (Commodore 64 Audio) support
sndio Enable support for the media-sound/sndio backend
tremor Build vorbis support using an integer implementation of the vorbis library (media-libs/tremor)

mp3blaster

sid Build with SID (Commodore 64 Audio) support

mpd

cdio Use libcdio for ISO9660 parsing support
chromaprint Enable ChromaPrint / AcoustID support
cue Enable CUE sheet support
curl Support for web stream listening
eventfd Use the eventfd function in MPD's event loop
faad Use external faad library for AAC decoding
fifo Support writing audio to a FIFO
fluidsynth Enables Fluidsynth MIDI software synthesis (discouraged)
gme Enables support for media-libs/game-music-emu for playing various video game music formats.
id3tag Support for ID3 tags
inotify Use the Linux kernel inotify subsystem to notice changes to mpd music library
lame Support for MP3 streaming via Icecast2
libmpdclient Enable support for remote mpd databases
libsoxr Enable the libsoxr resampler
mpg123 Enable support for mp3 decoding over media-sound/mpg123
network Enables network streaming support
nfs Enable support for the Network File System
openmpt OpenMPT decoder plugin
pipe Support writing audio to a pipe
pipewire PipeWire support
qobuz Build plugin to access qobuz
recorder Enables output plugin for recording radio streams
sid Build with SID (Commodore 64 Audio) support
signalfd Use the signalfd function in MPD's event loop
snapcast Snapcast audio plugin
sndio Enable support for the media-sound/sndio backend
soundcloud Build plugin to access soundcloud
systemd Enable support for systemd socket activation
twolame Support twolame MPEG-2 encoding
webdav Enable using music from a WebDAV share
wildmidi Enable MIDI support via wildmidi

mpfc

wav Enable wav audio codec support

mpg123

int-quality Use rounding instead of fast truncation for integer output, where possible

musescore

jumbo-build Combine source files to speed up build process, requires more memory
omr Enable PDF import (OMR - optical music recognition)
osc Enable OSC remote control protocol
portmidi Enable support for building against media-libs/portmidi
sf3 Enable SoundFont 3 support using media-libs/libvorbis
sfz Enable experimental SFZ sampler
webengine Use dev-qt/qtwebengine for embedded web browser

ncmpc

async-connect Enable asynchronous connect
chat-screen Enable the chat screen
help-screen Enable the help screen
key-screen Enable key editor screen
library-screen Enable library screen
lyrics-screen Enable lyrics screen
mouse Enable curses getmouse support
outputs-screen Enable the outputs screen
search-screen Enable search screen
song-screen Enable song viewer screen

ncmpcpp

clock Enable clock screen
lto Build with link-time optimisation
outputs Enable outputs screen
visualizer Enable visualizer screen with sound wave/frequency spectrum modes

ncspot

clipboard Use the system clipboard to e.g. share a link
cover Support displaying the album cover
mpris Allow ncspot to be controlled via MPRIS API
ncurses Use cursive/ncurses-backend instead of crossterm or pancurses
notify Show what's playing via a notification

patchage

jack-dbus Use Jack via D-Bus instead of libjack

picard

discid Enable reading the ID of the inserted CD
fingerprints Enable calculation and lookup of AcoustID fingerprints

pithos

keybinder Use keybinder to enable global key bindings

pms

regex Enable regular expression searches

puddletag

acoustid Use media-libs/chromaprint for acoustic fingerprinting
quodlibet Enables support for editing media-sound/quodlibet databases

pulseaudio

daemon Build the pulseaudio binary (not-needed for pipewire-pulse)
glib Add support to dev-libs/glib-based mainloop for the libpulse client library, to allow using libpulse on glib-based programs. Build the GSettings PA module.
ofono-headset Build with oFono HFP backend for bluez 5, requires net-misc/ofono.

pulseaudio-daemon

X Build the X11 publish module to export PulseAudio information through X11 protocol for clients to make use. Don't enable this flag if you want to use a system wide instance. If unsure, enable this flag.
alsa-plugin Request installing media-plugins/alsa-plugins with PulseAudio plugin enabled. This ensures that clients supporting ALSA only will use PulseAudio.
aptx aptX (HD) over Bluetooth (many Android compatible headphones), requires media-plugins/gst-plugins-openaptx.
asyncns Use libasyncns for asynchronous name resolution.
elogind Use sys-auth/elogind for giving each session a PA client
equalizer Enable the equalizer module (requires sci-libs/fftw and sys-apps/dbus).
fftw Enable the virtual surround sink module (requires sci-libs/fftw).
gdbm Use sys-libs/gdbm to store PulseAudio databases. Recommended for desktop usage. This flag causes the whole package to be licensed under GPL-2 or later.
glib Build the GSettings PA module.
gstreamer Build GStreamer-based RTP protocol module which supports more advanced RTP features like OPUS payload encoding.
ldac LDAC over Bluetooth (primarily Sony headphones), requires media-plugins/gst-plugins-ldac.
ofono-headset Build with optional oFono HFP backend for bluez 5, requires net-misc/ofono.
oss Enable OSS sink/source (output/input). Deprecated, upstream does not support this on systems where other sink/source systems are available (i.e.: Linux). The padsp wrapper is now always build if the system supports OSS at all.
ssl Use dev-libs/openssl to provide support for RAOP (AirPort) streaming.
system-wide Allow preparation and installation of the system-wide init script for PulseAudio. Since this support is only supported for embedded situations, do not enable without reading the upstream instructions at https://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/WhatIsWrongWithSystemWide/ .
systemd Build with sys-apps/systemd support to replace standalone ConsoleKit.
webrtc-aec Uses the webrtc.org AudioProcessing library for enhancing VoIP calls greatly in applications that support it by performing acoustic echo cancellation, analog gain control, noise suppression and other processing.

pulseeffects

bs2b Enable use of media-libs/libbs2b for the crossfeed FX
calf Enable use of media-plugins/calf for adding various FX
doc Install packages needed to display built-in user documentation
rnnoise Enable use of media-libs/rnnoise for the neural network-based noise-reduction FX
rubberband Enable use of media-libs/rubberband for the pitch-shifting FX
webrtc Enable use of media-plugins/gst-plugins-webrtc for various voice-enhancement FX
zamaudio Enable use of media-plugins/zam-plugins for the maximizer FX

qmidiarp

lv2 Enables Ladspa V2 plugins.

qmmp

analyzer Enable visual analyzer
archive Enable archiving plugin via app-arch/libarchive.
bs2b Enable Bauer stereophonic-to-binaural headphone filter
cover Enable album cover support
crossfade Enable crossfade effect when switching tracks
cue enable CUE sheet parsing
dbus Enable DBus notifiications and MPRIS support
enca Detects the character encoding automatically
game Enable Game music support
gnome Enable Gnome hotkey support (requires Qt5DBus)
lyrics Fetch track lyrics from the web
midi Enable midi support using wildmidi library
notifier Enable qmmps' notifier system
pipewire Enable PipeWire output plugin
projectm Enable projectm music visualization plugin
qsui Enable QMMP simple UI
qtmedia Enable playback via dev-qt/qtmultimedia
scrobbler Enable audioscrobbler/last.fm support
shout Enable shoutcast plug-in via media-libs/libshout.
sid Build with SID (Commodore 64 Audio) support
sndfile Enable wav playback support via media-libs/libsndfile
soxr Use the SoX resampling library
stereo Enable stereo effect
tray Build tray icon
xmp Enable module files renderer (modplug replacement)

qpwgraph

trayicon Build support for tray icon

qsampler

libgig Enable libgig support for loading Gigasampler files and DLS (Downloadable Sounds) Level 1/2 files

qtractor

aubio Enable media-libs/aubio support
dssi Enable support for DSSI Soft Synth Interface
rubberband Enable support for in-place audio clip pitch-shifting through the rubberband library

rhythmbox

daap Build the local network music sharing plugin which uses the DAAP protocol using net-libs/libdmapsharing

scream

pcap Support sniffing packets from network using net-libs/libpcap

shntool

alac Add support for Apple Lossless Audio Codec files
mac Add support for Monkey's Audio files
shorten Add support for the shorten audio compressor

snapcast

client Build and install Snapcast client component
server Build and install Snapcast server component
tremor Build with TREMOR version of vorbis

snd

notcurses Terminal interface via dev-cpp/notcurses
s7 Enable the s7 extension language (a version of Scheme)

sonic-visualiser

id3tag Enables ID3 tagging with id3tag library

sox

amr Enables Adaptive Multi-Rate Audio support
id3tag Enables ID3 tagging with id3tag library
sndio Enable support for sndio
twolame Enables twolame support (MPEG Audio Layer 2 encoder)

split2flac

enca Try to guess the charset using enca
flake Add support for Flake, alternative FLAC encoder
mac Add support for Monkey's Audio files
replaygain Support for Replay Gain metadata, for relative volume adjustment

spotify

local-playback Allows playing local files with the Spotify client
pax-kernel Triggers a paxmarking of the main Spotify binary
pulseaudio Controls the dependency on pulseaudio or apulse

strawberry

moodbar Enable moodbar support
vlc Enable media-video/vlc backend

supercollider

emacs Enable the SCEL user interface
gedit Enable the SCED user interface
gpl3 Build GPL-3 licensed code (recommended)
server Build with internal server
vim Enable the SCVIM user interface
webengine Enable the internal help system using QtWebengine

teamspeak-client

system-libcxx Use sys-libs/libcxx instead of shipped libs.
system-quazip Use dev-libs/quazip instead of shipped libs.

teamspeak-server

tsdns Install TeamSpeaks own DNS service for handling multiple virtual servers.

upmpdcli

thirdparty Enable streaming from Qobuz and Tidal external services

vimpc

boost Use boost instead of C++11 libraries

vorbis-tools

kate Adds support for Ogg Kate subtitles via libkate.
ogg123 Build ogg123 player, needs libao and curl

wildmidi

player Install the wildmidi player

xmms2

airplay Support for airplay format
fluidsynth Enable fluidsynth support (MIDI)
gme Support for various game audio formats using media-libs/game-music-emu
ices Icecast source output plugin
libvisual Install xmms2-libvisual for use with the 'visualization' effect
mac Support for Monkey's Audio (APE) format using media-sound/mac
mlib-update Enable building of xmms2-mlib-updater client
server Build xmms2 player daemon (otherwise only clients are built)
sid Support for C64 SID using media-libs/libsidplay
tremor Support Vorbis using an alternate fixed-point decoder with media-libs/tremor
vocoder Phase vocoder effect plugin
xml Enable support for various XML based playlists and sources: RSS, XSPF

xwax

alsa Adds support for ALSA audio input/output.
cdda Sets runtime dependencies to support decoding audio from a compact disc.
fallback Sets runtime dependencies to support decoding "other" audio files.
mp3 Sets runtime dependencies to support decoding MP3 audio.
oss Adds support for OSS (open sound system) audio input/output.

yarock

mpv Enable media-video/mpv backend
phonon Enable media-libs/phonon backend
vlc Enable media-video/vlc backend

yoshimi

lv2 Add support for Ladspa V2

zynaddsubfx

dssi Enable support for DSSI Soft Synth Interface

media-tv

kodi

airplay enable AirPlay support
bluetooth Enable JSON-RPC over BT for remote control connected via bluetooth
bluray Enable playback of Blu-ray filesystems
caps Use sys-libs/libcap to bind to privileged ports as non-root
cec Enable support for HDMI-CEC devices via libcec
dav1d Enables AV1 decoding via media-libs/dav1d
eventclients Install full set of Kodi python evenclients and evenclients examples
gbm Use the Graphics Buffer Manager for EGL on KMS.
gles Use simplified OpenGLES instead of full-scale OpenGL
libusb Use virtual/libusb for usb device hotplug support. This flag should only be enabled if you're running a non-Linux kernel or you don't want to use udev.
lirc Enable support for IR remote controls using app-misc/lirc
mariadb Enable support store of media library metadata on local or remote MariaDB
mysql Enable support store of media library metadata on local or remote MySQL
nfs Enable NFS client support
optical Enable Audio CD playback, optical disks detection and reading (CD-ROM, Video CD, and others), and ISO optical disk images direct reading. DVD disks may require additional 'udf' flag.
pipewire Enable pipewire support
power-control Enable control of shutdown, reboot, suspend, and hibernate
raspberry-pi Enable support for the Raspberry Pi
system-ffmpeg Use system ffmpeg instead of the bundled one
udev Use udev rules to handle devices' permissions and hotplug support. Unless you know what you're doing do not disable this flag on Linux kernels. This is provided as an option for completeness.
udf Enable UDF support. Required for playing blurays.
upower Use sys-power/upower to get battery level and active power source
webserver Enable internal webserver
xslt Enable metadata XSLT scrapers support with dev-libs/libxslt

linuxtv-dvb-apps

alevt Build videotext decoder

mythtv

alsa Allows MythTV to directly output sound to ALSA devices
asi Support for DVEO ASI recorder
autostart Use a custom autostart configuration
cec Allows control of CEC enabled TVs via HDMI
ceton Ceton InfiniTV 4 a CableCARD-enabled tuner support
debug Instructs Qt to use the 'debug' target
fftw Support visualizations via sci-libs/fftw
hdhomerun Silicondust USA Inc.network-attached tuner support
ieee1394 Firewire enabled Cable boxe support
jack Allows MythTV to use JACK as your sound output device
java BD-J support for Blu-ray discs
lcd Enable use of app-misc/lcdproc data display
lirc LIRC remote control device support
nvdec Enable NVDEC (NVCUVID) hardware accelerated video decoding
perl Build the perl bindings for MythTV
vbox V@Box Communications network-attached tuner devices support
vpx Enable VP8/VP9 support for media-libs/libvpx
wrapper Use Ubuntu mythtfrontend wrapper
x265 Enable h265 encoding using x265
xmltv Support media-tv/xmltv TV listing - not used by Schedules Direct]

tvheadend

capmt Enable support for capmt (dvbapi) protocol
constcw Enable support for the constcw protocol
cwc Enable support for the cwc (newcamd) protocol
ddci Enable support for DDCI hardware
dvbcsa Enable decryption of the DVB Common Scrambling Algorithm
dvben50221 Enable support for hardware CAM
hdhomerun Enable support for the HDHomeRun device
imagecache Enable support for image caching
iptv Enable support for Internet Protocol TV
satip Enable support for IP-based Satellite TV
timeshift Enable TimeShift support
uriparser Use dev-libs/uriparser
vpx Enable transcoding with the VP8/VP9 video codecs
x264 Enable transcoding with the H.264 video codec
x265 Enable transcoding with the HEVC video codec
xmltv Use media-tv/xmltv

v4l-utils

bpf Enables support for IR BPF decoders.

xmltv

ar Argentina tv listing grabber
ch-search Grabber for Switzerland
eu-epgdata include fanart URLs for some European countries.
eu-xmltvse Grabbber for Europe [replaces eu-dotmedia and se-tvzon]
fi Finland tv listing grabber (0.6.1 add ampparit telsu)
fi-sv Grabber for Finland (Swedish)
fr France tv listing grabber
huro Hungarian tv listing grabber
is Iceland tv listing grabber
it Italy tv listing grabber (RUV)
it-dvb Italy tv listing grabber
na-dd North America tv listing grabber
na-dtv North America Direct TV grabber
na-tvmedia Grabber for North America (TVMedia)
pt-vodafone Grabber for Portugal (Vodafone)
tr Turkey (Digiturk) tv listing grabber
tv-check enable GUI checking
tv-combiner enable grabbers combiner
tv-pick-cgi enable CGI support
uk-tvguide UK and Ireland tv listing grabber using TV Guide website
zz-sdjson Grabber for schedulesDirect.org SD-JSON service (many countries)
zz-sdjson-sqlite Grabber for schedulesDirect.org SD-JSON service (sqlite DB)

media-video

aegisub

uchardet Enable charset discovery via app-i18n/uchardet

aravis

fast-heartbeat Enable faster heartbeat rate.
gstreamer Build the GStreamer plugin.
packet-socket Enable packet socket support.
viewer Build the GTK+-based video viewer.

bluray_info

mpv Build bluray_player, powered by media-video/mpv

chaplin

transcode Enable DVD ripping and transcoding

droidcam

gtk Build the dev-cpp/gtkmm:3.0 client.

dvd_info

libmpv Build DVD player using libmpv

dvdrip

fping Enables fping support for cluster rendering
subtitles Enables support for subtitle ripping

ffdiaporama

openclipart Support openclipart database

ffmpeg

amf Enables support for AMD's Advanced Media Framework (AMF)
amr Enables Adaptive Multi-Rate Audio support
amrenc Enables Adaptive Multi-Rate Audio encoding support with media-libs/vo-amrwbenc.
appkit Enables Apple AppKit framework
bluray Enable playback of Blu-ray filesystems
bs2b Enables media-libs/libbs2b based Bauer stereo-to-binaural filter.
cdio Enables audio CD grabbing with dev-libs/libcdio.
chromaprint Enables audio fingerprinting support with media-libs/chromaprint.
chromium Builds libffmpeg.so to enable media playback in Chromium-based browsers like Opera and Vivaldi.
codec2 Enables codec2 low bit rate speech codec support via media-libs/codec2.
cpudetection Enables runtime CPU detection (useful for bindist, compatibility on other CPUs)
cuda Enables CUDA-based acceleration. Mostly used for specific filters.
dav1d Enables AV1 decoding via media-libs/dav1d.
fdk Use external fdk-aac library for AAC encoding
flite Adds a text-to-speech filter based on app-accessibility/flite.
frei0r Enable frei0r wrapping in libavfilter
fribidi Enables fribidi support in the drawtext filter.
gcrypt Enables gcrypt support: Needed for rtmp(t)e support if openssl, librtmp or gmp is not used.
glslang Use dev-util/glslang to compile GLSL
gme Enables support for media-libs/game-music-emu for playing various video game music formats.
gpl Build GPL code. Should be enabled unless you require LGPL binaries.
hardcoded-tables Use pre-calculated tables rather than calculating them on the fly. It results in an increase of approximately 15% in the size of libavcodec, the main library impacted by this change. It enables savings in table generation time, done once at codec initialization, since by hardcoding the tables, they do not need to be computed at runtime. However, the savings are often negligible (~100k cycles is a typical number) especially when amortized over the entire encoding/decoding operation. Improvements are being made to the runtime initialization, and so over time, this option will have an impact on fewer and fewer codecs.
iec61883 Support for FireWire DV/HDV input device using media-libs/libiec61883.
kvazaar Enables media-libs/kvazaar based HEVC encoder.
lcms Enable ICC profile support via media-libs/lcms.
libaom Enables media-libs/libaom based AV1 codec support.
libaribb24 Enables ARIB text and caption decoding via media-libs/aribb24.
libdrm Enables x11-libs/libdrm support for better screen grabbing and hardware accelerated codecs.
libilbc Enables iLBC de/encoding via media-libs/libilbc.
libplacebo Adds flexible GPU-accelerated processing filter based on media-libs/libplacebo.
librtmp Enables Real Time Messaging Protocol using librtmp (media-video/rtmpdump) in addition to FFmpeg's native implementation.
libsoxr Enables audio resampling through media-libs/soxr.
libtesseract Enables the OCR filter via app-text/tesseract.
libv4l Uses media-libs/libv4l for video4linux instead of direct calls. Adds support for more devices via the userspace library.
libxml2 Uses dev-libs/libxml2 to enable dash demuxing support.
lv2 Enables lv2 audio filter wrapper.
mipsdspr1 Enables MIPS DSP ASE R1 optimizations.
mipsdspr2 Enables MIPS DSP ASE R2 optimizations.
mipsfpu Enables floating point MIPS optimizations.
mmal Enables Multi-Media Abstraction Layer (MMAL) decoding support: Available e.g. on the Raspberry Pi.
network Enables network streaming support
opencl Enable OpenCL support
openh264 Enables H.264 encoding suppoprt via media-libs/openh264.
openssl Enables dev-libs/openssl support. Adds support for encrypted network protocols (TLS/HTTPS).
pic Force shared libraries to be built as PIC (this is slower)
postproc Build and install libpostproc.
qsv Enable Intel Quick Sync Video via media-libs/intel-mediasdk (ffmpeg versions older than, and including, 5.1) or media-libs/oneVPL (ffmpeg version newer than 5.1).
rav1e Enables AV1 encoding support via media-video/rav1e.
rubberband Adds time-stretching and pitch-shifting audio filter based on media-libs/rubberband.
shaderc Use media-libs/shaderc to compile GLSL
snappy Enable app-arch/snappy support. Required for e.g. Vidvox Hap encoder.
sndio Enable support for the media-sound/sndio backend
srt Enable support for Secure Reliable Transport (SRT) via net-libs/srt
ssh Enable SSH/sftp support via net-libs/libssh.
svt-av1 Enables AV1 encoding support via media-libs/svt-av1.
truetype Enables drawtext filter via media-libs/freetype and media-libs/harfbuzz.
twolame Enables MP2 encoding via media-sound/twolame as an alternative to the internal encoder.
vidstab Enables video stabilization filter using vid.stab library (media-libs/vidstab).
vmaf Enables Netflix's perceptual video quality assessment filter using the library (media-libs/libvmaf).
vpx Enables VP8 and VP9 codec support using libvpx: Decoding does not require this to be enabled but libvpx can also be used for decoding; encoding requires this useflag to be enabled though.
x265 Enables HEVC encoding with media-libs/x265.
zeromq Enables net-libs/zeromq support with the zmq/azmq filters.
zimg Enables media-libs/zimg based scale filter.
zvbi Enables media-libs/zvbi based teletext decoder.

ffmpeg-chromium

cpudetection Enables runtime CPU detection (useful for bindist, compatibility on other CPUs)
gpl Build GPL code. Should be enabled unless you require LGPL binaries.
mmal Enables Multi-Media Abstraction Layer (MMAL) decoding support: Available e.g. on the Raspberry Pi.

guvcview

qt5 Build with Qt5 interface instead Gtk+

handbrake

fdk Support for encoding AAC using media-libs/fdk-aac.
gstreamer Support for the streaming media framework from media-libs/gstreamer.
gtk Install the GTK UI, ghb.
libav-aac Support for encoding AAC using libav's internal encoder.
numa Adds support for x265's NUMA capabilities.
x265 Support for encoding h265 using media-libs/x265.

libva-utils

examples Build and install decode, encode, videoprocess and other VA-API examples.
putsurface Build and install putsurface tool.
vainfo Build and install vainfo tool.

makemkv

java Handle additional Blu-ray protection mechanisms involving Java

mjpegtools

sdlgfx Enables y4mhist to display a graphical histogram

mjpg-streamer

http-management Enable experimental HTTP management option
input-control Plugin giving ability to control camera movement (only specific cameras)
input-file Plugin that watches given directory and send it's content
input-http Plugin that takes http-input
input-ptp2 Plugin that sends video stream from PTP2 compatible camera
input-raspicam Raspberry Pi camera support via the input_raspicam plugin
input-testpicture Plugin for sending compiled in, test pictures
input-uvc Plugin that sends video stream from UVC compatible camera
output-autofocus Auto focusing plugin
output-file Plugin that saves received content under given location
output-http Small HTTP server plugin which sends WWW directory content and streams image content
output-rtsp Plugin which provides a mechanism to take snapshots with a trigger from a UDP packet
output-udp Plugin receiving content over UDP and storing to a directory
output-viewer Plugin which allows to see output with viewer
output-zmqserver Plugin which provides zmqserver processing
www Installs WWW content
wxp-compat Enable camera WXP compatible format

motion

mariadb Add mariadb database support
mmal Enables Multi-Media Abstraction Layer (MMAL) decoding support: Available e.g. on the Raspberry Pi.

motiontrack

multiprocess Enables multi-process support (SMP/cluster) for motiontrack programs

mplayer

bl Blinkenlights video output
bluray Enable playback of Blu-ray filesystems
bs2b Enable Bauer stereophonic-to-binaural headphone filter
cdio Use libcdio for CD support (instead of cdparanoia)
cdparanoia Enable cdparanoia (audio CD ripper) support
cpudetection Enables runtime CPU detection (useful for binpkgs, compatibility on other CPUs)
dvdnav Use forked libdvdnav, navigate menus in GUIs
enca Enables support for charset discovery and conversion
faac Use external faac library for AAC encoding
faad Use external faad library for AAC decoding
libmpeg2 Build support for mpeg2 over media-libs/libmpeg2 rather than using ffmpeg.
live Enables live.com streaming media support
md5sum Enables md5sum video output
mng MNG input support
network Enables network streaming support
osdmenu Enables support for on-screen display (OSD) menus
pnm Add PNM video output option, to create PPM/PGM/PGMYUV images
pvr Enable Video4Linux2 MPEG PVR
radio Enable V4L2 radio interface and support
rar Enable Unique RAR File Library
rtc Enables usage of the linux real time clock. The alternative is software emulation of rtc
rtmp Enables RTMPDump Streaming Media support
shm Enable support for shm
tga Enables Targa video output
toolame Enable toolame MPEG-2 encoding
tremor Enable internal support for Vorbis
twolame Enable twolame MPEG-2 encoding
vcd Enables VCD support
vidix Support for vidix video output
yuv4mpeg Enables yuv4mpeg video output
zoran Enables ZR360[56]7/ZR36060 video output

mpv

archive Enable support for various archive formats via app-arch/libarchive
bluray Enable playback of Blu-ray filesystems
cli Enable the command-line player
drm Enable Kernel Mode Setting / Direct Rendering Manager based video outputs
egl Enable support for various EGL-based video outputs / backends
gamepad Enable gamepad input support
libmpv Enable the shared library and headers (used by frontends / plugins)
libplacebo Enable support for GPU accelerated video rendering with media-libs/libplacebo
lua Enable Lua scripting, OSC (On Screen Controller) GUI, and net-misc/yt-dlp support
mmal Enable Multi-Media Abstraction Layer (MMAL) decoding support: Available e.g. on the Raspberry Pi
opengl Enable support for OpenGL-based video backends (Note: deprecated for X11, USE=egl provides the newer support for -gpu-api=opengl)
pipewire Enable sound support via native PipeWire backend
raspberry-pi Enable support for the Raspberry Pi
rubberband Enable high quality pitch correction via media-libs/rubberband
sdl Enable media-libs/libsdl2 based video and audio outputs (Note: these outputs exist for compatibility reasons only, avoid if possible)
sixel Enable support for the sixel video backend using media-libs/libsixel
sndio Enable sound support via media-sound/sndio
tools Install extra tools: mpv_identify.sh, mpv_idet.sh, and umpv
uchardet Enable subtitles charset discovery via app-i18n/uchardet
zimg Enable libzimg support (for vf_fingerprint)

noad

libmpeg2 Build support for mpeg2 through media-libs/libmpeg2 rather than using media-video/ffmpeg

obs-studio

browser Enable browser source support via (precompiled) CEF.
decklink Build the Decklink plugin.
fdk Build with LibFDK AAC support.
mpegts Enable native SRT/RIST mpegts output.
pipewire Build with PipeWire support.
python Build with scripting support for Python 3.
qsv Build with Intel Quick Sync Video support.
speex Build with Speex noise suppression filter support.
ssl Build with TLS/SSL support for RTMPS connections.
vlc Build with VLC media source support.
websocket Build with WebSocket API support.

peek

keybinder Enable support for global hotkeys using dev-libs/keybinder

pipewire

X Enable audible bell for X11
echo-cancel Enable WebRTC-based echo canceller via media-libs/webrtc-audio-processing
extra Build pw-cat/pw-play/pw-record
flatpak Enable Flatpak support
gsettings Use gsettings (dev-libs/glib) to read/save used modules (useful for e.g. media-sound/paprefs
jack-client Install a plugin for running PipeWire as a JACK client
jack-sdk Use PipeWire as JACK replacement
liblc3 Allow loading LC3 plugins via media-sound/liblc3
lv2 Allow loading LV2 plugins via media-libs/lv2
modemmanager Combined with USE=bluetooth, allows PipeWire to perform telephony on mobile devices.
pipewire-alsa Replace PulseAudio's ALSA plugin with PipeWire's plugin
roc Enable roc support for real-time audio streaming over the network, using media-libs/roc-toolkit. See https://gitlab.freedesktop.org/pipewire/pipewire/-/wikis/Network#roc
sound-server Provide sound server using ALSA and bluetooth devices
ssl Enable raop-sink support (needs dev-libs/openssl)
system-service Install systemd unit files for running as a system service. Not recommended.

qmplay2

audiofilters Build with AudioFilters module
avdevice Build FFmpeg module with libavdevice suport
cdio Build with AudioCD module
cuvid Build with CUVID module
extensions Build with Extensions module and enable other plugins
gme Build Chiptune with GME support
inputs Build with Inputs module
libass Build with SSA/ASS subtitles rendering support
notifications Build additional notifications module
pipewire Build with PipeWire support
shaders Compile Vulkan shaders using media-libs/shaderc
sid Build Chiptune with SIDPLAY support
videofilters Build with VideoFilters module
visualizations Build with Visualizations module

rav1e

capi Build the C-API library and header file

rtmpdump

gnutls Use GnuTLS instead of OpenSSL for Cryptography
ssl Enable Cryptographic features
tools Enable installation of various binary tools in addition to librtmp library

simplescreenrecorder

asm Enable x86 assembly optimisation.
vpx Enable VP8 codec support via media-libs/libvpx.

totem

python Build dev-lang/python using plugins (dbusservice for notifications and MPRIS control, interactive python console and opensubtitles lookup)

transcode

mjpeg Enables mjpegtools support
nuv NuppelVideo container format demuxing
pic disable optimized assembly code that is not PIC friendly
postproc Build with ffmpeg libpostproc support

vdr

alternatechannel Use alternate channel on record
bidi fribidi support, for languages, written from right to left
demoplugins Install demo and example plugins coming with vanilla vdr
graphtft support for vdr-graphtft plugin up from version 0.1.7
html Install HTML documentation
keyboard enable keyboard support as remote device
mainmenuhooks Allows to replace main menu entries by some special plugins (like epgsearch, extrecmenu, ...)
menuorg Enables support for the media-plugins/vdr-menuorg
menuselection adds support for menu hotkeys of double digits
naludump Removes NALU fill data from h.264-Streams of TS files
permashift permanent timeshift by recording live TV into RAM, need plugin media-plugins/vdr-permashift
pinplugin Support for media-plugins/vdr-pin
resumereset rreset resume of EOF
ttxtsubs support for media-plugins/vdr-ttxtsubs
verbose enable full output on compile

vidify

dbus Support local MPRIS players
mpv Use python-mpv as backend for vidify
vlc Use python-vlc as backend for vidify
zeroconf Use an external network player

vlc

X Enable support for e.g. fullscreen mode via X and the X C-language binding. It does not build a graphical interface
aom Enable AV1 encoding/decoding support using media-libs/libaom
archive Enable support for libarchive stream extractor
aribsub Enable support for decoding ARIB STD-B24 subtitles
bluray Enable libbluray for Blu-ray disc support
chromaprint Enable libchromaprint for Chromaprint based audio fingerprinter support
chromecast Enable experimental support for Google Chromecast
dav1d Enable support for media-libs/dav1d AV1 decoder
dc1394 Enable IIDC cameras support
directx Enable Win32 DirectX, D3D11va and DxVA2 support
dvbpsi Enable support for Mpeg-TS files (.ts, .m2ts, .mts) via media-libs/libdvbpsi
encode Enable streaming-output support and videolan manager to control multiple streams from within one instance
faad Enable AAC audio decoding library support via media-libs/faad2
fdk Enable the Fraunhofer AAC codec library
fluidsynth Enable Fluidsynth MIDI software synthesis (with external sound fonts)
gcrypt Enable cryptography support via libgcrypt
gme Enable support for media-libs/game-music-emu for playing various video game music formats
gstreamer Enable GStreamer based decoding support (currently supports only video decoding)
kate Adds support for Ogg Kate subtitles via libkate
kms Enable kernel mode setting video output plugin via x11-libs/libdrm
libplacebo Enable support for GPU accelerated video rendering with media-libs/libplacebo
libtar Uses libtar instead of the built-in tar reader for reading custom skins
libtiger Enable Ogg Kate subtitles rendering using libtiger
linsys Enable support for Linux Linear Systems Ltd. SDI and HD-SDI input cards
live Enable live555 streaming media support (client support for rtsp)
loudness Enable loudness normalisation according to the EBU R128 standard using media-libs/libebur128
lua Enable Lua scripting support, needed for including support for Jamendo (online music platform) and similar things
macosx-notifications Enable Mac OS X notifications module (formerly growl)
matroska Enable matroska support using reference libraries (fallback on other existing matroska support if disabled, i.e., matroska enabled FFmpeg)
mpeg Add libmpeg2 support for mpeg-1 and mpeg-2 video streams
nfs Enable support for nfs protocol via net-fs/libnfs
omxil Enable OpenMAX Integration Layer codec module
optimisememory Enable optimisation for memory rather than performance
projectm Enable the projectM visualization plugin
run-as-root Allows vlc to start for root. Don't enable this unless you have a very specific (e.g. embedded) need for it!
sdl-image Enable sdl image video decoder (depends on sdl)
sftp Enable libssh2 to support SFTP file transfer
shout Enable libshout output
sid Adds support for playing C64 SID files through media-libs/libsidplay:2
skins Enable support for the skins2 interface
soxr Enable SoX Resampler support via media-libs/soxr
srt Enable support for Secure Reliable Transport (SRT) via net-libs/srt
tremor Enable tremor, a fixed-point version of the Ogg Vorbis decoder
twolame Enable twolame support (MPEG Audio Layer 2 encoder)
upnp Enable support for the Intel SDK stack based UPnP discovery module instead of CyberLink
vpx Enable the decoder(s) from the WebM VP8 / VP9 Codec SDK
x265 Support X265 Encoder
zeroconf Enable support for zero-configuration networking via avahi
zvbi Enable support for teletext subtitles via the zvbi library

webcamoid

headers Install development headers
libuvc Build with libuvc support
qtaudio Enable audio capture/play via dev-qt/qtmultimedia
qtcamera Enable video capture/play via dev-qt/qtmultimedia
v4lutils Build with V4L-utils support
videoeffects Build video effects

wireplumber

system-service Install systemd unit files for running as a system service. Not recommended.

x264-encoder

avs enable AvxSynth support in the AviSynth input module
ffmpegsource Enable ffmpegsource aka ffms support, disables lavf
interlaced Enable interlaced encoding support, this can decrease encoding speed by up to 2%

xine-ui

vdr Enables Video Disk Recorder support

net-analyzer

2ping

server Install the server init scripts.

argus-clients

ft Enable support for flow packets through net-analyzer/flow-tools

barnyard

sguil Enable sguil (The Analyst Console for Network Security Monitoring) support

barnyard2

gre Enable GRE support
mpls Enable support for mpls networks
sguil Enable sguil (The Analyst Console for Network Security Monitoring) support

bwm-ng

csv Enable csv output
html Enable html output

cacti

doc install html documentation

check_mk_agent

apache_status Install check_mk-agent apache-status plugin.
inventory Install check_mk-agent linux inventory plugin.
logwatch Install check_mk-agent logwatch plugin.
mysql Install check_mk-agent mysql plugin.
nfsexports Install check_mk-agent nfsexports plugin.
postgres Install check_mk-agent postgres plugin.
smart Install check_mk-agent S.M.A.R.T plugin.
zypper Install check_mk-agent zypper plugin.

echoping

http enable support for http protocol.
icp enable support for ICP (used to monitor proxies).
priority enable socket priority support.
smtp enable support for SMTP protocol.
tos enable support for TOS (TYpe Of Service).

ettercap

plugins Install ettercap plugins (et_*.so)

flowgrind

pcap Enable packet capturing support using net-libs/libpcap

fprobe

messages enable console messages

goaccess

geoipv2 Enable support for GeoIP2 through dev-libs/libmaxminddb
getline Use GNU getline() to parse full line requests

gr-fosphor

glfw enable GLFW based interface

greenbone-feed-sync

cron Adds file to enable daily cron job to update Greenbone Community Feed's data"

gvm

cli Command Line Interface for OpenVAS Scanner
gsa Greenbone Security Assistant (WebUI)
ospd Enable support for scanner wrappers

hexinject

experimental Install experimental packets.tcl
tools Install hex2raw and prettypacket tools

httping

tfo Enable support for TCP Fast Open

hydra

gcrypt Enable radmin2 support through dev-libs/libgcrypt
libssh Enable SSH support through net-libs/libssh
mongodb MongoDB support through dev-libs/mongo-c-driver

icinga2

console Adds support for line-editing in the console
jumbo-build Combine source files to speed up build process, requires more memory
lto Adds support for link time optimization
mail Allows for mailing of alerts
mariadb Enable support for the mariadb database backend
nano-syntax Adds support for syntax used in the nano editor
plugins Adds support for nagios plugins

ipsumdump

nanotimestamp Enable timestamps with nano-second resolution

linkchecker

sqlite Mozilla Bookmark parsing

monitoring-plugins

dns Install net-dns/bind-tools required for monitoring DNS servers. Disabling the flag does not remove any plugins.
fping Install net-analyzer/fping required for fancy ping monitoring. Disabling the flag does not remove any plugins.
game Install games-util/qstat required for monitoring FPS servers. Disabling the flag does not remove any plugins.
snmp Install dev-perl/Net-SNMP and net-analyzer/net-snmp required for monitoring SNMP values. Disabling the flag does not remove any plugins.
ssh Install net-misc/openssh required for monitoring SSH servers. Disabling the flag does not remove any plugins.

mtr

ipinfo Disable support for IP address lookups
jansson Enable JSON output support through dev-libs/jansson

munin

asterisk Install the packages required for monitoring Asterisk. Disabling the flag does not remove any plugin files.
cgi Install the CGI-compatible scripts for on-the-fly generation of web pages and graphs. This is only meaningful if the minimal USE flag is disabled.
dhcpd Install dev-perl/Net-IP, dev-perl/HTTP-Date and net-misc/dhcp to monitor DHCP lease usage. This only works if the server is on the same system as the node, so the server is also brought in. Disabling the flag does not remove any plugin file.
doc Build and install a local copy of the HTML documentation for the whole software. This requires dev-python/sphinx to process the documentation sources.
http Install dev-perl/libwww-perl required for monitoring HTTP-based services such as Apache and nginx. Disabling the flag does not remove any plugin file.
ipmi Install sys-apps/ipmitool required for monitoring IPMI sensors. Disabling the flag does not remove any plugin file.
ipv6 Add support for IPv6 in munin-node. IPv6 support for the master is always enabled, but the node requires a newer version of dev-perl/Net-Server, capable of listening to IPv6 sockets.
irc Install the packages required for monitoring IRC. Disabling the flag does not remove any plugin files.
java Build the Java-based plugins to monitor JMX-compatible applications. Disabling the flag removes the jmx monitoring plugins.
memcached Install the packages required for memcached monitoring. Disabling the flag does not remove any plugin files.
minimal Only install munin-node and its plugins. This excludes the scripts to generate the web pages and the graphs.
mysql Install the packages required for monitoring MySQL. Disabling the flag does not remove any plugin files.
postgres Install the packages required for monitoring PostgreSQL. Disabling the flag does not remove any plugin files.
syslog Configure the node by default to log on syslog. This requires the presence of virtual/perl-Sys-Syslog. As of version 2.0.2, the master scripts only log to file, and not to syslog.

nagios-core

classicui use the classic web theme
lighttpd install www-servers/lighttpd config
web enable web interface

nagios-plugin-check_raid

3ware Support 3ware RAID controllers
aacraid Support Adaptec AAC-RAID controllers
dmraid Support Device-Mapper RAID
hpa Support HP Array controllers
hpsa Support HP SmartArray (CCISS) controllers
megaraid-sas Support LSI MegaRAID SAS controllers
mpt Support LSI MPT Fusion controllers
mpt-sas2 Support LSI SAS-2 controllers

nagios-plugins

nagios-dns Install net-dns/bind-tools required for monitoring DNS servers. Disabling the flag does not remove any plugin file.
nagios-game Install games-util/qstat required for monitoring FPS servers. Disabling the flag does not remove any plugin file.
nagios-ping Install net-analyzer/fping required for fancy ping monitoring. Disabling the flag does not remove any plugin file.
snmp Install dev-perl/Net-SNMP required for monitoring SNMP values. Disabling the flag does not remove any plugin file.
ssh Install net-misc/openssh required for monitoring SSH servers. Disabling the flag does not remove any plugin file.

nagios-plugins-linux-madrisan

curl Build check_docker which requires net-misc/curl
varlink Build check_podman which requires dev-libs/libvarlink

net-snmp

elf Enable the use of elf utils to check uptime on some systems
kmem Enable usage of /dev/kmem
mfd-rewrites Use MFD rewrites of mib modules where available
netlink Use dev-libs/libnl to fetch TCP statistics instead of using /proc/net/tcp (Linux only).
pcap Install snmppcap which reads from PCAP files and writes to the SNMP transport
pci Use libpci (from sys-apps/pciutils) to look up network interface description. This feature is only available on Linux.
pcre Add support for Perl Compatible Regular Expressions in process table filtering.
rpm Enable monitoring of app-arch/rpm. This flag requires the bzip2 and zlib flags to be enabled as well.
smux Enable support for the legacy smux protocol (superseded by agentx)
ucd-compat Build UCD compatibility library. Increases significantly the install size.

netdata

cloud Enable Netdata Cloud support
compression Enable compression via zlib
dbengine Enable the Netdata database engine
ipmi Install sys-apps/ipmitool required for monitoring IPMI sensors.
jsonc Enable optimization of JSON using dev-libs/json-c
lto Build with Link Time Optimization (LTO)
mongodb Enable support for the mongodb backend
nfacct Enable the nfacct plugin
nodejs Enable use of nodejs (which some plugins use)
prometheus Enable support for the Prometheus remote write backend
tor Enable monitoring of tor
xen Enable monitoring of xen

netperf

demo Emit interim results during the run. May affect results

nfdump

ftconv Build the flow-tools to nfdump converter
jnat Build nfudmp to support JunOS NAT event logging
nfpcapd Build nfpcapd collector to create netflow data from precollected pcap traffic
nfprofile Build nfprofile used by NfSen
nftrack Build nfprofile used by PortTracker
nsel Build nfudmp to support NSEL/NEL event data
readpcap Build nfcapd collector to read from pcap file instead ofnetwork data
sflow Build sflow collector sfcpad

nmap

libssh2 Enable SSH support through net-libs/libssh2
ncat Install the ncat utility
ndiff Install the ndiff utility
nping Install the nping utility
nse Include support for the Nmap Scripting Engine (NSE)
symlink Install symlink to nc
zenmap Install the GTK+ based nmap GUI, zenmap

nrpe

command-args Build support for specifying the command-line arguments from the Nagios/Icinga master. Make sure you understand the implications of this flag as it can be a security risk.

nsca

crypt Build support for crypted communication with nsca, through dev-libs/libmcrypt. It's recommended not to disable this flag unless all the communication will be handled in an absolutely safe environment.
minimal Only build and install the send_nsca command and not the daemon. This allows a very minimal install with no overhead when setting up a node.

openvas-scanner

snmp Build againts net-analyzer/net-snmp for "improved SNMP support"

ospd-openvas

notus Set systemd service file to use notus-scanner

ossec-hids

agent Build "agent" installation target (see package description)
hybrid Build "hybrid" installation target
local Build "local" installation target
server Build "server" installation target

pinger

gtk2 Install the gtkpinger GUI utility based on x11-libs/gtk+:2
gtk3 Install the gtkpinger GUI utility based on x11-libs/gtk+:3

pmacct

bgp-bins Link BGP daemon binaries
bmp-bins Link BMP daemon binaries
geoipv2 Enable support for GeoIP2 through dev-libs/libmaxminddb
jansson Enable support for JSON through dev-libs/jansson
kafka Enable support for Apache Kafka through dev-libs/librdkafka
l2 Enable Layer-2 features and support
ndpi Enable support for nDPI through net-libs/nDPI
nflog Enable support for NFLOG through uacctd
rabbitmq Enable support for RabbitMQ through net-libs/rabbitmq-c
st-bins Link Streaming Telemetry daemon binaries
traffic-bins Link IPv4/IPv6 traffic accounting binaries
zmq Enable support for ZeroMQ through net-libs/zeromq

pnp4nagios

icinga Build against net-analyzer/icinga2 instead of net-analyzer/nagios-core
nagios Build against net-analyzer/nagios-core (the default)

rrdcollect

exec Enable exec:/// support
librrd Use the librrd library from net-analyzer/rrdtool

rrdtool

graph Enable support for graphing functions
rados Enable support for librados from sys-cluster/ceph
rrdcached Build support for write-caching daemon
rrdcgi Build rrdcgi support

sancp

sguil Enable sguil (The Analyst Console for Network Security Monitoring) support

sarg

doublecheck Make sarg double check the data it manipulates and output a warning if an error is found
gd Enable support for graphs in reports through media-libs/gd
glob Disable to ignore wildcards in file names
pcre Enable support for regular expressions in the hostalias file through dev-libs/libpcre

scanlogd

nids Use net-libs/libnids for packet capturing
pcap Use net-libs/libpcap for packet capturing

sngrep

eep Enable EEP packet send/receive support
gnutls Use net-libs/gnutls to parse captured TLS packets

snort

active-response Enables support for automatically sending TCP resets and ICMP unreachable messages to terminate connections. Used with inline deployments.
control-socket Enables Snort's control socket.
file-inspect Enables extended file inspection capabilities.
flexresp3 Enables support for new flexable response preprocessor for enabling connection tearing for inline deployments. Replaces flexresp and flexresp2.
gre Enable support for inspecting and processing Generic Routing Encapsulation (GRE) packet headers. Only needed if you are monitoring GRE tunnels.
high-availability Enables high-availability state sharing.
inline-init-failopen Enables support to allow traffic to pass (fail-open) through inline deployments while snort is starting and not ready to begin inspecting traffic. If this option is not enabled, network traffic will not pass (fail-closed) until snort has fully started and is ready to perform packet inspection.
large-pcap-64bit Allows Snort to read pcap files that are larger than 2 GB. ONLY VALID FOR 64bit SYSTEMS!
libtirpc Build against net-libs/libtirpc for RPC support
linux-smp-stats Enable accurate statistics reporting through /proc on systems with multiple processors.
non-ether-decoders Enable decoding of non-ethernet protocols such as TokenRing, FDDI, IPX, etc.
open-appid Enable OpenAppID, an open, application-focused detection language and processing module for Snort that enables users to create, share, and implement application detection. Requires dev-lang/luajit.
perfprofiling Enables support for preprocessor and rule performance profiling using the perfmonitor preprocessor.
ppm Enables support for setting per rule or per packet latency limits. Helps protect against introducing network latency with inline deployments.
react Enables support for the react rule keyword. Supports interception, termination, and redirection of HTTP connections.
reload-error-restart Enables support for completely restarting snort if an error is detected during a reload.
shared-rep Enables the use of shared memory for the Reputation Preprocessor (Only available on Linux systems)
side-channel Enables Snort's side channel.
sourcefire Enables Sourcefire specific build options, which include --enable-perfprofiling and --enable-ppm.

suricata

af-packet Enable AF_PACKET support
af-xdp Enable AF_XDP support
bpf Enable support for eBPF (as well as XDP if supported by the kernel and the NIC driver) for low-level, high-speed packet processing
control-socket Enable unix socket
cuda Enable NVIDIA Cuda computations support
detection Enable detection modules
hyperscan Enable high-performance regex matching with Hyperscan
lz4 Enable support for compressed pcap logging using the LZ4 algorithm
nflog Enable libnetfilter_log support
nfqueue Enable NFQUEUE support for inline IDP
redis Enable Redis support

symon

perl Enables a generic perl symux client
symon Enables the system monitor. Offers no functionality but monitoring and forwarding of measured data
symux Enables the multiplexer which stores incoming symon streams on disk in RRD (net-analyzer/rrdtool) files

tcpdump

drop-root Drop privileges to pcap:pcap when run as root
smi Build with net-libs/libsmi to load MIBs on the fly to decode SNMP packets

tcpreplay

pcapnav Enable if you want the jump to byte offset feature via net-libs/libpcapnav
tcpdump Use net-analyzer/tcpdump for packet decoding feature

testssl

bundled-openssl Install precompiled versions of OpenSSL for greater testing coverage

tracebox

curl Build the curl component for uploading capture files using net-misc/curl
sniffer Build the sniffer component using net-libs/libnetfilter_queue

wireshark

androiddump Install androiddump, an extcap interface to capture from Android devices
bcg729 Use media-libs/bcg729 for G.729 codec support in RTP Player
capinfos Install capinfos, to print information about capture files
captype Install captype, to print the file types of capture files
ciscodump Install ciscodump, extcap interface to capture from a remote Cisco router
dftest Install dftest, to display filter byte-code, for debugging dfilter routines
dpauxmon Install dpauxmon, an external capture interface (extcap) that captures DisplayPort AUX channel data from linux kernel drivers
dumpcap Install dumpcap, to dump network traffic from inside wireshark
editcap Install editcap, to edit and/or translate the format of capture files
http2 Use net-libs/nghttp2 for HTTP/2 support
ilbc Build with iLBC support in RTP Player using media-libs/libilbc
libxml2 Use dev-libs/libxml2 for handling XML configuration in dissectors
lto Enable link time optimization
maxminddb Use dev-libs/libmaxminddb for IP address geolocation
mergecap Install mergecap, to merge two or more capture files into one
minizip Build with zip file compression support
netlink Use dev-libs/libnl
pcap Use net-libs/libpcap for network packet capturing (build dumpcap, rawshark)
plugins Install plugins
qt6 Build with Qt6 support instead of the default Qt5 for GUI support
randpkt Install randpkt, a utility for creating pcap trace files full of random packets
randpktdump Install randpktdump, an extcap interface to provide access to the random packet generator (randpkt)
reordercap Install reordercap, to reorder input file by timestamp into output file
sbc Use media-libs/sbc for playing back SBC encoded packets
sdjournal Install sdjournal, an extcap that captures systemd journal entries
sharkd Install sharkd, the daemon variant of wireshark
smi Use net-libs/libsmi to resolve numeric OIDs into human readable format
spandsp Use media-libs/spandsp for for G.722 and G.726 codec support in the RTP Player
sshdump Install sshdump, an extcap interface to capture from a remote host through SSH
text2pcap Install text2pcap, to generate a capture file from an ASCII hexdump of packets
tfshark Install tfshark, a terminal-based version of the FileShark capability
tshark Install tshark, to dump and analyzer network traffic from the command line
udpdump Install udpdump, to get packets exported from a source (like a network device or a GSMTAP producer) that are dumped to a pcap file
wifi Install wifidump, to dump and analyse 802.11 traffic

zabbix

agent Enable zabbix agent (for to-be-monitored machines)
agent2 Enable go-based zabbix agent 2 (for to-be-monitored machines)
frontend Enable zabbix web frontend
ipv6 Turn on support of IPv6
java Enable Zabbix Java JMX Management Gateway
libxml2 Use libxml2 client library
mbedtls Use net-libs/mbedtls as TLS backend
odbc Enable Database Monitor and use UnixODBC Library by default
openipmi Enable openipmi things
openssl Use dev-libs/openssl as TLS backend
proxy Enable proxy support
server Enable zabbix server
ssh SSH v2 based checks
static Build statically linked binaries

zmap

mongo Add support for storing in a mongo DB via dev-db/mongodb
redis Add support for storing in a redis DB via dev-libs/hiredis

net-dialup

accel-ppp

ipoe Build IPoE kernel module
libtomcrypt Support crypto algorithms through dev-libs/libtomcrypt instead of dev-libs/openssl
shaper Support for traffic shaping

freeradius

memcached Include dev-libs/libmemcached in caching drivers
mongodb Include support for MongoDB database
redis Include support for Redis database

freeradius-client

scp Add service type hints derived from username prefix
shadow Enable shadow password support

mgetty

fax Enables fax support
fidonet Enables FidoNet support

openl2tp

client Enable l2tp client.
dmalloc Enable debugging using dev-libs/dmalloc.
rpc Enable RPC control management. This flag is required for l2tpconfig to be built and used.
server Enable l2tp server.
stats Enable status files. Note: when they are used, this hampers performance of the daemon.

ppp

activefilter Enables active filter support
dhcp Installs PPP DHCP client plugin for IP address allocation by a DHCP server (see http://www.netservers.co.uk/gpl/)
eap-tls Enables support for Extensible Authentication Protocol and Transport Level Security (see http://www.nikhef.nl/~janjust/ppp/index.html)
gtk Installs GTK+ password prompting program that can be used by passprompt.so PPP plugin for reading the password from a X11 input terminal
radius Enables RADIUS support

xl2tpd

kernel Enable kernel interface for PPPoL2TP

net-dns

avahi

autoipd Build and install the IPv4LL (RFC3927) network address configuration daemon
bookmarks Install the avahi-bookmarks application (requires dev-python/twisted)
gtk Use gtk3 for the avahi utilities to build the avahi-ui-gtk3 library
howl-compat Enable compat libraries for howl
mdnsresponder-compat Enable compat libraries for mDNSResponder

bind

dlz Enables dynamic loaded zones, 3rd party extension
dnsrps Enable the DNS Response Policy Service (DNSRPS) API, a mechanism to allow an external response policy provider
dnstap Enables dnstap packet logging
fixed-rrset Enables fixed rrset-order option
geoip2 Enable GeoIP2 API from MaxMind
gssapi Enable gssapi support
json Enable JSON statistics channel
lmdb Enable LMDB support to store configuration for 'addzone' zones

bind-tools

gssapi Enable gssapi support

ddclient

examples Install various example files, like for cron.

dnsdist

dnscrypt Enable the ability to act as a DNSCrypt server
dnstap Enable support for dnstap
doh Enable support for dns over http via www-servers/h2o
lmdb Enable support for lmdb
regex Enable support for regular expression matching via dev-libs/re2
remote-logging Enable support for remote logging via dev-libs/protobuf
ssl Enable support for and encrypted client-server communication via dev-libs/libsodium

dnsmasq

auth-dns Add support for acting as an authorative DNS server.
conntrack Add support for Linux conntrack connection marking.
dhcp Enable support for acting as a DHCP server.
dhcp-tools Install extra command line tools for manually managing DHCP leases.
dnssec Enable support DNSSEC validation and caching.
dumpfile Include code to dump packets to a libpcap-format file for debugging
id Whether report *.bind CHAOS info to clients, otherwise forward such requests upstream instead
libidn2 Enable support for Internationalized Domain Names, via net-dns/libidn2 rather than net-dns/libidn
loop Include functionality to probe for and remove DNS forwarding loops
nettlehash Use hashing functions from dev-libs/nettle
script Enable support for calling scripts when leases change.
tftp Enables built in TFTP server for netbooting.

dnssec-validator

dlv Enable support for the DNSSEC look-aside validation
nsec3 Enable support for the NSEC3 Resource Record

getdns

getdns-query Add getdns_query tool
getdns-server-mon Add getdns_server_mon tool
libev Enable dev-libs/libev support
libevent Enable dev-libs/libevent support
libuv Enable dev-libs/libuv support
stubby Add Stubby DNS Privacy Deamon
unbound Enable net-dns/unbound libraries support

hash-slinger

ipsec Enable support for IPSECKEY records (ipseckey)
openpgp Enable support for OPENPGPKEY records (openpgpkey)
ssh Enable support for SSHFP records (sshfp)

idnkit

liteonly Compile and install lite library only

inadyn

mbedtls Use net-libs/mbedtls as tls provider.
openssl Use dev-libs/openssl as tls provider.

knot

cookies Enable the DNS cookie module (RFC 7873)
dnsproxy Enable the tiny DNS proxy module
dnstap Include support for the dnstap binary log format (http://dnstap.info/)
doh Enable DNS over HTTP (DoH) using libnghttp2
fastparser Use a zone file parser that is faster, but requires more memory and CPU time to compile
geoip Enable the Geography-based responses module
libidn2 If IDN support is enabled, use net-dns/libidn2 instead of net-dns/libidn
noudp Enable the module which can send empty truncated responses to UDP queries
onlinesign Enable the module that sign zones on the fly instead of pre-signing zone
queryacl Enable the module for query access control
quic Enable the DNS over QUIC (DoQ) module using libngtcp2
rrl Enable the response rate limiting module
stats Enable the server statistics module
synthrecord Enable the automatic forward/reverse records module
utils Install Knot utilities, such as kdig, kzonecheck, ...
whoami Enable the whoami response module
xdp Enable eXpress Data Path

knot-resolver

dnstap Build dnstap binary logging module
kresc Build (experimental) command-line client
nghttp2 DNS-over-HTTPS support

mydns

alias Enable David Phillips aliasing
status Enable the STATUS opcode to check server status

nsd

bind8-stats Enables BIND8 like NSTATS and XSTATS
dnstap Enable the structured binary log format
libevent Use libevent or libev, useful when zone count is high
minimal-responses If minimal responses are disabled, responses are more likely to get truncated, resulting in TCP fallback
munin Install a plugin for net-analyzer/munin to graph statistical data from nsd.
nsec3 Enable NSEC3 support
ratelimit Enables ratelimiting, based on query name, type and source
root-server Configure NSD as a root server

opendnssec

external-hsm Enables support for storing DNSSEC keys through an arbitrary non-portage PKCS#11 interface, specified through an environment variable
opensc Enables support for storing DNSSEC keys through a dev-libs/opensc PKCS#11 interface
signer Enables signing capabilities for OpenDNSSEC
softhsm Enables support for storing DNSSEC keys in a dev-libs/softhsm PKCS#11 object

pdns

lmdb Use LMDB as backend.
lua-records Enable LUA records.
remote Use a generic socket or pipe as a backend (via JSON RPC requests).
sodium Use dev-libs/libsodium for cryptography
tinydns Use a TinyDNS CDB database as backend.
tools Build optional tools (dnsscan, dnsscope, etc..).

pdns-recursor

dnstap Enable support for dnstap
sodium Use dev-libs/libsodium for cryptography

pdnsd

urandom Linux-only: use /dev/urandom (pseudo-random number generation) instead of the default use of random() PRNG.
symlink Actually replace /etc/resolv.conf with a symlink. Without this flag, the ebuild is a no-op.

unbound

dnscrypt Enable DNSCrypt support
dnstap Enable dnstap support
ecdsa Enable ECDSA support
ecs Enable EDNS client subnet support
gost Enable GOST support
http2 Enable HTTP/2 support for DoHnet-libs/nghttp2
redis Enable cache db backend which usesdev-libs/hiredis
tfo Enable TCP Fast Open client+server

net-firewall

arno-iptables-firewall

plugins Install optional plugins
rsyslog Install configuration snippet for app-admin/rsyslog

conntrack-tools

cthelper Use net-libs/libnetfilter_cthelper for userspace conntrack helper support
cttimeout Use net-libs/libnetfilter_cttimeout for conntrack timeout support

ebtables

perl Install the ebtables-save script which uses perl

firehol

ipset Use net-firewall/ipset.

firewalld

iptables Add support for net-firewall/iptables as firewall backend
nftables Add support for net-firewall/nftables as firewall backend

fwknop

client Build fwknop client
extras Install utility scripts and AppArmor policy for fwknopd
firewalld Use net-firewall/firewalld as the default server backend
gdbm Use sys-libs/gdbm to store fwknopd digest cache
gpg Enable GPG support via app-crypt/gpgme
iptables Use net-firewall/iptables as the default server backend
nfqueue Enable UDP-only NFQUEUE server mode (no net-libs/libpcap dependency)
server Build fwknopd server
udp-server Enable UDP-only server mode (no net-libs/libpcap dependency)

ipt_netflow

natevents Netflow NAT translation events (NEL) support

iptables

conntrack Build against net-libs/libnetfilter_conntrack when enables the connlabel matcher
netlink Build against libnfnetlink which enables the nfnl_osf util
nftables Support nftables kernel interface
pcap Build against net-libs/libpcap which enables the nfbpf_compile util

nftables

doc Create man pages for the package (requires app-text/asciidoc)
json Enable JSON support via dev-libs/jansson
modern-kernel Install init scripts for 3.18 or higher kernels with atomic rule updates
xtables Add libxtables support to try to automatically translate rules added by iptables-compat

pglinux

cron Install cron script

shorewall

init Adds the capability to place the firewall in a safe state prior to bringing up the network interfaces
ipv4 Installs everything needed to create a full IPv4 firewall
ipv6 Adds the capability to create a full IPv6 firewall (requires net-firewall/shorewall ipv4 USE flag)
lite4 Installs everything needed to just *run* an IPv4 compiled firewall script created with net-firewall/shorewall ipv4 USE flag
lite6 Installs everything needed to just *run* an IPv6 compiled firewall script created with net-firewall/shorewall ipv6 USE flag

ufw

examples Example ufw config files
ipv6 IPv6 support for iptables

net-fs

autofs

dmalloc Enable debugging with the dmalloc library
ldap Install LDAP module
libtirpc Use TiRPC library instead of SunRPC
mount-locking Enable locking to prevent corruption of /etc/mtab in the presence of concurrent auto-mounting. If enabled, recursive auto-mounting (eg. using autofs to bind or loop mount a filesystem which is itself auto-mounted) is not possible.
sasl Enable SASL support in the LDAP module

cifs-utils

ads Enable Active Directory support and create cifs.idmap binary - idmap support
caps Enable sys-libs/libcap-ng support
creds cifs credentials support
python Enable support for python and install python tools

cvmfs

server Install the cvmfsd program and init script

libnfs

utils Build/install nfs-{cat,ls,cp} utils

netatalk

pgp Add support pgp authentication module
quota Add support for user quota on various filesystems
shadow Add shadow support
ssl Use dev-libs/openssl to provide DHX User Access Modules. These are not used with most recent versions of OS X and can be kept disabled without risks.
tracker Add support for spotlight like tracker

nfs-utils

junction Enable NFS junction support in nfsref
ldap Add ldap support
libmount Link mount.nfs with libmount
nfsdcld Enable nfsdcld NFSv4 clientid tracking daemon
nfsidmap Enable support for newer nfsidmap helper
nfsv4 Enable support for NFSv4
nfsv41 Enable support for NFSv4.1
uuid Support UUID lookups in rpc.mountd

openafs

apidoc Build API documentation using app-doc/doxygen. May take a *long* time to build.
bitmap-later Enable fast startup of file server by not reading bitmap till needed.
fuse Build fuse client.
kauth Install the DEPRECATED kauth server, PAM modules, and utilities
modules Build libafs kernel module. Disable only if you know what you're doing: without this module OpenAFS client will not work.
namei Enable namei fileserver instead of inode fileserver. You should disable this option only if compatibility with inode format AFS storage is required.
pthreaded-ubik Enable installation of pthreaded ubik applications.
supergroups Enable support for nested pts groups.
tsm Enable use of the Tivoli TSM API libraries from app-backup/tsm for butc support. AMD64 only.
ubik-read-while-write Enable vlserver read from db cache during write locks (EXPERIMENTAL)

s3fs

gnutls Enable net-libs/gnutls crypto backend
nettle Use dev-libs/nettle network functions with GnuTLS.
nss Enable dev-libs/nss crypto backend

samba

addc Enable Active Directory Domain Controller support
ads Enable Active Directory support
ceph Enable support for Ceph distributed filesystem via sys-cluster/ceph
client Enables the client part
cluster Enable support for clustering
glusterfs Enable support for Glusterfs filesystem via sys-cluster/glusterfs
gpg Use app-crypt/gpgme for AD DC
iprint Enabling iPrint technology by Novell
json Enable json audit support through dev-libs/jansson
profiling-data Enables support for collecting profiling data
quota Enables support for user quotas
regedit Enable support for regedit command-line tool
snapper Enable vfs_snapper module (requires sys-apps/dbus)
spotlight Enable support for spotlight backend
system-heimdal Use app-crypt/heimdal instead of bundled heimdal.
system-mitkrb5 Use app-crypt/mit-krb5 instead of app-crypt/heimdal.
unwind Enable libunwind usage for backtraces
winbind Enables support for the winbind auth daemon

net-ftp

frox

transparent Enable transparent proxying of data connections

ftpbase

zeroconf Enable support for zero-configuration networking via Avahi.

lftp

convert-mozilla-cookies Install the convert-mozilla-cookies script and its run-time dependencies
verify-file Install the verify-file script and its run-time dependencies

proftpd

authfile Enable support for the auth-file module
ban Enable support for the mod_ban module
case Enable support for the mod_case module
copy Enable support for the mod_copy module
ctrls Enable support for the mod_ctrls and mod_ctrls_admin modules
deflate Enable support for the mod_deflate module
diskuse Enable support for the mod_diskuse module
dso Enable support for the mod_dso module
dynmasq Enable support for the mod_dynmasq module, for dynamically updating MasqueradeAddress for dyndns-like scenarios)
exec Enable support for the mod_exec module. WARNING: this could be a security risk
ident Enable support for the mod_ident module
ifsession Enable support for the ifsession module
ifversion Enable support for the mod_ifversion module
log-forensic Enable support for the mod_log_forensic module, log only suspicious actions.
memcache Enable support for the mod_memcache module, for using memcached servers
msg Enable support for the mod_msg module, allows system users to send messages to connected clients via the ftpdctl program.
qos Enable support for the mod_qos module
ratio Enable support for the mod_ratio module
readme Enable support for the mod_readme module
rewrite Enable support for the rewrite module
sftp Enable support for the mod_sftp module and optionally mod_sftp_sql and mod_sftp_pam if matching USE flags are enabled
shaper Enable support for the mod_shaper module
sitemisc Enable support for the sitemisc module
sodium Use dev-libs/libsodium for password encryption an key exchange
softquota Enable support for the quotatab module
unique-id Enable support for the mod_unique_id module, every connection gets unique ID.
vroot Enable support for the virtual root module

pure-ftpd

anondel Permit anonymous to delete files
anonperm Permit anonymous to change file permissions
anonren Permit anonymous to rename files
anonres Permit anonymous to resume file transfers
implicittls Enable TLS on Port 990
noiplog Disables logging of IP addresses
paranoidmsg Display paranoid messages instead of normal ones
resolveids Resolve UIDs/GIDs
sysquota Enables system quota support (needs sys-fs/quota)
vchroot Enable support for virtual chroot (possible security risk)

tftp-hpa

client Compile and install the tftp client
server Compile and install the tftp server

yafc

ssh Build with SFTP support

net-im

biboumi

udns Asynchronously resolve domain names using net-libs/udns

bitlbee

libevent Use libevent for event handling
nss Prefer dev-libs/nss as SSL/TLS provider
otr Enable support for encrypted conversations
plugins Enable support for plugins
purple Use libpurple instead of the built-in IM protocol support
twitter Enable Twitter protocol support

choqok

attica Build Open Collaboration Services plugin using kde-frameworks/attica
share Enable support for a share menu using kde-frameworks/purpose
telepathy Enable support for the real-time communication framework telepathy

coturn

mongodb Enable support for the mongodb database
redis Enable support for the redis database

dino

gpg Enable OpenPGP encryption plugin
http Enable HTTP file upload plugin
notification-sound notification sounds plugin
omemo Enable OMEMO encryption plugin
rtp Enable Audio/Video calls over XMPP using RTP

ejabberd

captcha Support for CAPTCHA Forms (XEP-158) on registration
full-xml Use XML features in XMPP stream (ex: CDATA), requires XML compliant clients
mssql Enable Microsoft SQL Server support (via ODBC) for data storage
mysql Enable MySQL support for data storage
odbc Enable ODBC support to access data storage
postgres Enable PostgreSQL support for data storage
redis Enable Redis support for transient data
roster-gw Turn on workaround for processing gateway subscriptions
sip Enable SIP support
sqlite Enable SQLite database support
stun Enable STUN/TURN support
zlib Enable Stream Compression (XEP-0138) using zlib

err

irc Pull optional dependencies, needed for IRC backend

gajim

crypt End to end encryption and GPG encryption
geolocation Sharing your location
jingle Audio and video calls
omemo Install dependencies for OMEMO encryption plugin
remote Controling Gajim instance from command line with gajim-remote
rst Generating XHTML output from RST code
spell Spellchecking of composed messages
upnp Ability to request your router to forward port for file transfer
webp Support WebP avatars

libcommuni

qml Install optional qml files.
uchardet Use app-i18n/uchardet, which is upstreams default, instead of dev-libs/icu, which makes impossible to run tests.

pidgin

gadu Enable Gadu Gadu protocol support
groupwise Enable Novell Groupwise protocol support
gstreamer Enables voice and video sessions
gtk Builds Pidgin, the GTK+ interface
meanwhile Enable meanwhile support for Sametime protocol
ncurses Build finch, console interface
prediction Enable Contact Availability Prediction plugin
python Build libgnt (GLib Ncurses Toolkit used by finch) with python scripting support
xscreensaver Use X screensaver protocol extension to monitor idle/active status based on mouse/keyboard events
zephyr Enable Zephyr protocol support

profanity

gpg Enable OpenPGP encryption
omemo Enable OMEMO encryption
omemo-qrcode Enable exchanging OMEMO information via QR code
otr Enable encrypted conversations using Off-The-Records messaging
python Enable Python plugins support

prosody

libevent Use libevent for event handling

psi

aspell Enable spellchecking using app-text/aspell
enchant Enable spellchecking using app-text/enchant
extras Enable Psi+ patchset
hunspell Enable spellchecking using app-text/hunspell
iconsets Install additional iconsets, some of them have no clear licensing
webengine Enable themed, html-based chatlogs using dev-qt/qtwebengine
whiteboarding Enable experimental interactive SVG drawing
xscreensaver Use X screensaver protocol extension to monitor idle/active status based on mouse/keyboard events

psimedia

extras Enable Psi+ mode (required when built for Psi+)

qtox

X Enable auto-away support
notification Use snorenotify for desktop notifications
spellcheck Enable spell checking support

spectrum2

frotz Enables the Z-Engine backend.
irc Enables the IRC backend, based on net-im/libcommuni.
purple Enables the libpurple backend, based on net-im/pidgin.
sms Enables the SMS backend, based on app-mobilephone/smstools.
twitter Enables the Twitter backend.
whatsapp Enables the WhatsApp backend, based on net-im/transwhat.

telegram-desktop

enchant Use the app-text/enchant spell-checking backend instead of app-text/hunspell
fonts Use builtin patched copy of open-sans fonts (overrides fontconfig)
qt6 Build with Qt6 support
qt6-imageformats Add support for HEIF, AVIF and JpegXL by bundling kde-frameworks/kimageformats

telepathy-connection-managers

gadu Enable Gadu Gadu protocol support.
icq Enable ICQ IM protocol support.
irc Enable Internet Relay Chat (IRC) support.
meanwhile Enable meanwhile support for Sametime protocol.
msn Enable MSN Messenger IM protocol support.
sip Enable SIP/SIMPLE messaging and calling.
sipe Enable Sip Exchange Protocol.
steam Enable Steam Chat support.
xmpp Enable XMPP protocol handler (this is also Google Talk).
yahoo Enable Yahoo! messaging support.
zeroconf Enable Link-Local Messaging via the zeroconf or Bonjour protocol.

tkabber

plugins Enables installation the extra plugins

toxic

audio-notify Enables native sound notifications
games Enables some small mini-games
llvm Enables support for LLVM Address Sanitizer
notification Enables desktop notifications with libnotify, with sound support.
qrcode Enables QR code support
sound Enables audio calling
video Enables video calling

zoom

bundled-libjpeg-turbo Use bundled libturbojpeg instead of media-libs/libjpeg-turbo
bundled-qt Use bundled Qt and icu instead of system-wide libs
opencl Use OpenCL for virtual background support (virtual/opencl)

net-irc

anope

ldap Build LDAP modules for e.g. opertypes
sql Build modules which require SQL
ssl Provide SSL services using OpenSSL
tre Use dev-libs/tre for regular expressions

atheme-services

cracklib Enable nickserv/cracklib module for enforcing strong account passwords
largenet Enable support/tweaks for large networks
ldap Enable ldap-backed authentication module
perl Install a perl module which wraps around the services' XML-RPC interface

epic5

archive Use app-arch/libarchive to use zip and tar archives from scripts.

hexchat

libcanberra Enable sound event support using media-libs/libcanberra
plugin-checksum Build Checksum plugin (needs plugins)
plugin-fishlim Build FiSHLiM plugin (needs plugins )
plugin-sysinfo Build SysInfo plugin (needs plugins)
theme-manager Build the theme manager (mono)

inspircd

argon2 Enable Argon2 hashes in modules
gnutls Enable TLS support
ldap Enable LDAP support
maxminddb Add support for geolocation using libMaxMindDB
mbedtls Add support for TLS using the mbedTLS library
mysql Enable MySQL database backend
pcre2 Add support for Perl Compatible Regular Expressions 2
postgres Enable PostgreSQL database backend
re2 Add support for Google RE2 regular expressions library
regex-posix Add support for POSIX Regular Expressions
regex-stdlib Add support for C++ stdlib regular expressions
sqlite Enable Sqlite database backend
ssl Enable SSL support
sslrehashsignal Enable rehashing SSL module by SIGUSR1
tre Enable support for TRE, a lightweight, robust, and efficient POSIX compliant regexp matching library

ircii

lto Build using Link Time Optimizations (LTO)

iroffer-dinoex

admin Compile with HTTP Admin
blowfish Compile with blowfish encryption support
chroot Compile with chroot support
http Compile with HTTP server support
memsave Compile with memory protection
telnet Compile with Telnet server support

irssi

otr Adds support for a loadable IRC otr module
proxy Adds support for a loadable IRC proxy module

kvirc

dcc-video Support video connections over DCC protocol
phonon Support Phonon for audio output

limnoria

crypt Enables user authentication with GPG

ngircd

ident Enables support for net-libs/libident
irc-plus Enables support for the IRC+ protocol (needs virtual/libiconv)
strict-rfc Strict RFC compliance; may harm compatibility

psybnc

multinetwork Adds support for multiple networks
oidentd Adds support for oidentd
scripting Adds scripting support

quassel

bundled-icons Use icon themes bundled with Quassel, rather than depending on system packages.
crypt Support core->network per-channel and per-query blowfish encryption via app-crypt/qca SLOT 2.
dbus Support desktop notifications via the StatusNotifier D-Bus service (used by most modern desktop environments).
gui Build the Qt5 GUI client for quassel. If this USE flag is disabled, the GUI is not built, and cannot be used. You might want to disable this on the server, but you need it enabled on the client.
monolithic Build standalone client with integrated core, no external quasselcore needed. Only useful if you don't want to use Quassel's client/server model. The server and X flags are not needed in this case but it is possible to enable them too.
oxygen Support the Oxygen icon set that was the default for KDE4.
server Build the server binary. If this USE flag is disabled, the 'core' server binary for quassel is not built, and cannot be used. You need this enabled on the server, but you might want to disable it on the client.
snorenotify Support for Snore notification framework.
urlpreview Use QtWebEngine rendering engine for showing URL thumbnails.

rbot

aspell Use aspell instead of ispell in the "spell" plugin for rbot. The vanilla plugin uses ispell, but enabling this flag makes it use the ispell interface from aspell instead.
cal Add dependency over a package providing the /usr/bin/cal command, which is needed to enable the "cal" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
figlet Add dependency over app-misc/figlet, which is used by the "figlet" plugin for rbot. If the USE flag is disabled the plugin will be unable to use figlet; if toilet is also disabled, the plugin will be disabled.
fortune Add dependency over games-misc/fortune-mod, which is needed to enable the "fortune" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
host Add dependency over net-dns/bind-tools (providing /usr/bin/host), which is needed to enable the "host" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
nls Build and install translation for the messages coming from the bot and its plugins (through dev-ruby/ruby-gettext).
timezone Add dependency over dev-ruby/tzinfo to enable the "time" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
toilet Add dependency over app-misc/toilet, which is used by the "figlet" plugin for rbot. If the USE flag is disabled the plugin will be unable to use toilet; if figlet is also disabled, the plugin will be disabled.
translator Add dependency over dev-ruby/mechanize, which is needed to enable the "translator" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.

soju

moderncsqlite Use moderncsqlite, a cgo-free port of SQLite

unrealircd

class-nofakelag Enable an unsupported class::options flag called “nofakelag” allowing you to grant fakelag exemption to normal user (instead of just opers).
operoverride Enable OperOverride extension
operoverride-verify Enable requiring opers to invite themselves to +s/+p channels
prefixaq Enable chanadmin and chanowner prefixes
showlistmodes Display channel modes in /LIST (only configured at compiletime)

weechat

alias Enable plugin for alias control
buflist Enable buflist plugin
charset Enable encoding conversions
enchant Enable spell checker plugin via Enchant instead of GNU Aspell
exec Enable exec plugin
fifo Enable FIFO support (sh pipes)
fset Enable fast set plugin
irc Enable IRC protocol support
logger Enable support for logging
relay Enable relay plugin (experimental)
scripts Build infrastructure for scripting
trigger Enable trigger plugin
typing Enable typing plugin
xfer Enable xfer plugin support

znc

zlib Enable mod_deflate-like gzip support for znc's web interface using sys-libs/zlib.

net-libs

aqbanking

ebics Enable support for Electronic Banking Internet Communication Standard (EBICS)

axtls

cgi-lua Enables lua backed cgi for axhttpd server
cgi-php Enables php backed cgi for axhttpd server
httpd Enables axhttpd web server component
static Statically build axhttpd server

c-client

chappa Enable Eduardo Chappa's patches for use with mail-client/alpine (mainly adds support for maildir)
doc Install RFCs related to IMAP
topal Enable support for net-mail/topal for use with mail-client/alpine

canlock

header-parser Build article header parsers
legacy Build legacy API (v2 compatible)

cvm

vpopmail Enable vpopmail support

czmq

drafts Build draft API, which may change at any time without any notice, and is therefore not recommended for normal use. (requires draft support in net-libs/zeromq as well)
http-client Build support for HTTP client using net-misc/curl
http-server Build support for HTTP server using net-libs/libmicrohttpd
nss Use dev-libs/nss for SHA instead of an internal implementation
uuid Enable UUID support using sys-apps/util-linux

daq

afpacket Build the AFPacket data acquisition module. Functions similar to the PCAP module but with better performance. Snort can run unprivileged when using this module. AFpacket supports both inline and passive modes.
dump Build the Dump data acquisition module. The dump DAQ allows you to test the various inline mode features available in 2.9 Snort like injection and normalization.
ipq Build the IPQ data acquisition module. IPQ is the old way to process iptables packets for inline deployments. Snort can not run unprivileged when using this module.
nfq Build the NFQ data acquisition module. NFQ is the new way to process iptables packets for inline deployments. Snort can not run unprivileged when using this module.
pcap Build the PCAP data acquisition module.

davix

tools Install additional tools

freaklabs-chibiarduino

promisc Enable promisc in the config file for packet sniffing

glib-networking

gnome Extract HTTP/HTTPS/SOCKS proxy configuration stored using GSettings
libproxy Use net-libs/libproxy for getting the HTTP/HTTPS/SOCKS proxy configuration

gnome-online-accounts

gnome Use gnome-base/gnome-control-center to set GNOME online accounts preferences

gnutls

dane Build libgnutls-dane, implementing DNS-based Authentication of Named Entities. Requires net-dns/unbound
openssl Build openssl compatibility libraries
pkcs11 Add support for PKCS#11 through app-crypt/p11-kit
sslv2 Support for the old/insecure SSLv2 protocol
sslv3 Support for the old/insecure SSLv3 protocol
test-full Enable full test mode
tls-heartbeat Enable the Heartbeat Extension in TLS and DTLS
tools Build extra tools

gssdp

man Generate man page for tools

ldns

dane Enable DNS-based Authentication of Named Entities (DANE) support
ecdsa Enable ECDSA support
ed25519 Enable ED25519 support
ed448 Enable ED448 support
gost Enable GOST support

libbitcoinconsensus

asm Enable assembly for optimization

libetpan

liblockfile Enable support for liblockfile library
lmdb Use dev-db/lmdb as cache DB

libgsasl

gcrypt Use dev-libs/libgcrypt for low-level crypto
ntlm Add support for Microsoft's NTLM mechanism using net-libs/libntlm

libiio

aio Enable asynchronous IO support

libiscsi

rdma Enable infiniband support via sys-cluster/rdma-core

libisds

openssl Use dev-libs/openssl as crypto backend instead of app-crypt/gpgme and dev-libs/libgcrypt

libmicrohttpd

epoll Support epoll() system call
eventfd Use EventFD for efficient inter-thread communication
thread-names Assign thread names to internal threads, useful for dependent apps debugging

libnids

glib Use dev-libs/glib for multiprocessing support
libnet Include code requiring net-libs/libnet

libnma

pkcs11 Enable PKCS#11 support in certificate chooser via app-crypt/gcr

liboauth

bindist Alias for the nss USE flag, since there are license compliancy trouble when using OpenSSL.
curl If enabled, net-misc/curl is used thorugh the libcurl library; if it's not, the curl command is used instead. Some features are only available when using the library, but using it as library requires matching SSL implementations.
nss Use Mozilla NSS (dev-libs/nss) as hash library; if this is disabled, dev-libs/openssl is used instead.

liboping

filecaps Allow non-root users to use [n]oping utility.
ncurses Build ncurses-based version of oping utility (requires sys-libs/ncurses)

libpcap

netlink Use dev-libs/libnl to put wireless interfaces in monitor mode.
rdma Enable RDMA capture support using sys-cluster/rdma-core
remote Enable remote packet capture which may expose libpcap-based applications to attacks by malicious remote capture servers!
yydebug Enable parser debugging code

libprotoident

tools Build and install command-line tools

libproxy

duktape Use dev-lang/duktape for PAC parsing
gnome Enable support for reading proxy settings from GNOME
kde Enable support for reading proxy settings from KDE

libqmi

mbim Support QMI over Mobile Broadband Interface Model (MBIM)
qrtr Support QMI over IPC Router bus (QRTR)

libsoup

gssapi Enable GSSAPI support
samba Use net-fs/samba for NTLM Single Sign-On
sysprof Enable profiling data capture support using dev-util/sysprof-capture

libsrtp

aesicm Use AES ICM cryptographic algorithm
console Use /dev/console instead of stdout for error messages
nss Use NSS crypto primitives
openssl Use OpenSSL crypto primitives
syslog Use syslog for error messages

libssh

gcrypt Use dev-libs/libgcrypt as TLS provider
gssapi Enable gssapi support
mbedtls Use net-libs/mbedtls as TLS provider
pcap Build with PCAP output support
server Build with SSH server support
sftp Build with SFTP support

libssh2

gcrypt Use dev-libs/libgcrypt instead of dev-libs/openssl
mbedtls Use net-libs/mbedtls instead of dev-libs/openssl

libtorrent-rasterbar

dht Enable DHT (distributed hash table) support

libtrace

numa Use sys-process/numactl

libupnp

blocking-tcp Do not use async socket calls
reuseaddr Allow clean restarts by binding the socket with SO_REUSEADDR
samples Install sample applications

libvncserver

24bpp Enable 24bpp support
filetransfer Enable support for TightVNC's file transfer protocol
gcrypt Use dev-libs/libgcrypt as crypto backend
lzo Enable LZO support via dev-libs/lzo instead of using internal miniLZO implementation

libwebsockets

access-log Support generating Apache-compatible access logs
client The client part of the library and libwebsockets-test-client
extensions Compile with extensions (permessage-deflate)
generic-sessions With the Generic Sessions plugin
http-proxy Support for rewriting HTTP proxying
http2 Support the HTTP/2 protocol
lejp With the Lightweight JSON Parser
libev Support event loops via dev-libs/libev
libevent Support event loops via dev-libs/libevent
libuv Support asynchronous I/O via dev-libs/libuv
mbedtls Use mbedTLS replacement for OpenSSL
peer-limits Track peers and restrict resources a single peer can allocate
server-status Support json + jscript server monitoring
smtp Provide SMTP support
sqlite3 Require SQLITE3 support

loudmouth

asyncns Use net-libs/libasyncns for asynchronous name resolution.
openssl Enable dev-libs/openssl support instead of gnutls (which is the default).

mbedtls

cmac Enable block cipher-based message authentication code algorithm
havege Enable the HAVEGE random generator. Warning: the HAVEGE random generator is not suitable for virtualized environments
programs Build PolarSSL programs

neon

libproxy Add support for net-libs/libproxy
pkcs11 Add support for PKCS#11 using dev-libs/pakchois

nghttp2

hpack-tools Install HPACK (header compression) helper tools
utils Install nghttp, nghttpd and nghttpx

ngtcp2

openssl Provide SSL support using OpenSSL (requires dev-libs/openssl)

nodejs

corepack Enable the experimental corepack package management tool
inspector Enable V8 inspector
lto Build with link-time optimisation
npm Enable NPM package manager
pax-kernel Enable building under a PaX enabled kernel
snapshot Enable snapshot creation for faster startup
system-icu Use system dev-libs/icu instead of the bundled version
system-ssl Use system OpenSSL instead of the bundled one
systemtap Enable SystemTAP/DTrace tracing

ntirpc

gssapi Include support for RPCSEC GSS
rdma Include support for RDMA RPC

paho-mqtt-c

high-performance The debugging aids internal tracing and heap tracking are not included

pjproject

amr Inlcude AMR codec in the build
epoll Use /dev/epoll ioqueue on Linux (experimental)
g711 Include G.711 codecs in the build
g722 Include G.722 codec in the build
g7221 Include G.722.1 codec in the build
g729 Include G.729 codec via net-libs/bcg729
ilbc Include iLBC codec in the build
l16 Include Linear/L16 codec family in the build
libyuv Include libyuv in the build
openh264 Include Open H.264 support in the build
resample Include resampling implementations in the build
silk Include SILK support in the build
v4l2 Include Video4Linux v2 support in the build
vpx Include VP8 and VP9 codec support in the build
webrtc Enable WebRTC support

qxmpp

omemo Enable OMEMO encryption

rabbitmq-c

tools Builds cli tools to interact with brokers

rtrlib

ssh Enable SSH support

shairplay

playfair Add support for handling fairplay handshake (used in for example screen mirroring)

telepathy-qt

farstream Enable support for audio/video calls via farstream

tox

av Adds support for audio and video.
daemon Enable the DHT Bootstrap Daemon.
dht-node Enables DHT Bootstrap Node.
key-utils Builds utilities to create custom keys and profiles
log-debug Log level: 4
log-error Log level: 1
log-info Log level: 3
log-trace Log level: 5
log-warn Log level: 2

udns

tools Build and install dnsget, ex-rdns and rblcheck tools

wandio

http Build support for reading files over HTTP using net-misc/curl

webkit-gtk

examples Install the MiniBrowser example application
gamepad Enable gamepad input support via dev-libs/libmanette
jumbo-build Combine source files to speed up build process

wvstreams

boost Use dev-libs/boost to provide TR1-compatible functional interface. This USE flag is only needed with GCC earlier than version 4.1, or with other compilares not providing said interface.

xdp-tools

tools Install various helper tools rather than just libxdp.

xrootd

ceph Enable suport for sys-cluster/ceph (XrdCeph plugin)
fuse Enable the sys-fs/fuse filesystem driver
http Enable http protocol support
libxml2 Use dev-libs/libxml2 for XML parsing (preferred) instead of bundled tinyxml
macaroons Enable support for macaroons with dev-libs/libmacaroons
scitokens Enable support for scitokens with dev-cpp/scitokens-cpp
server Install xrootd server and related plug-ins
xrdec Enable erasure coding support (XrdEc plugin) with dev-libs/isa-l

zeromq

drafts Build draft API, which may change at any time without any notice, and is therefore not recommended for normal use.
libbsd Use strlcpy() from dev-libs/libbsd instead of internal implementation.
pgm Build PGM (Pragmatic General Multicast)extention, a protocol for reliable multicast transport of data over IP networks.
sodium Use dev-libs/libsodium for cryptography

net-mail

courier-imap

trashquota include deleted messages, and the Trash folder, in the estimated quota usage for maildirs

cyrus-imapd

backup Enable backup service support
calalarm Enable CalDAV alarm support
http Enable http and http/2 support
replication Enable replication support
server Enable building server binaries
sieve Enable sieve support
xapian Enable Xapian search engine support

dbmail

sieve Enable sieve filter support

dovecot

argon2 Add support for ARGON2 password schemes
lucene Add lucene full text search (FTS) support using dev-cpp/clucene
managesieve Add managesieve protocol support
rpc Add support for NFS quotas
sieve Add sieve support
solr Add solr full text search (FTS) support
stemmer Add libstemmer support (for FTS)
textcat Add libtextcat language guessing support for full text search (FTS)

fetchmail

socks Enable support for socks proxy
tk Enable support for Tk GUI toolkit, in particular it installs fetchmailconf

gnubiff

password Enable save passwords to connect mail servers in user space

lbdb

abook Enables app-misc/abook support
bbdb Include support for app-emacs/bbdb
evo Add support for mail-client/evolution
finger Enables finger support

mailutils

clients Build client programs - frm maidag mail sieve messages readmsg dotlock movemail mimeview mh
kyotocabinet Enable Kyoto Cabinet database support
servers Build server programs - imap4d pop3d comsatd
tokyocabinet Enable Tokyo Cabinet database support

mboxgrep

dmalloc Enable debugging using dev-libs/dmalloc

mu

emacs Install the mu4e mail client

notmuch

apidoc Provide doxygen generated API docs
crypt Support decryption and verification of PGP/MIME messages and in Emacs UI - encryption; support also S/MIME signature verification since version 0.22
doc Install API documentation
emacs Install Emacs UI (the main one)
mutt Install helper script for Mutt
nmbug Install experimental tag sharing / pseudo-bug-tracking script for Notmuch (see http://notmuchmail.org/nmbug/)

qmailadmin

maildrop Filter spam using maildrop

tpop3d

authexternal Enable authentication by an external program
flatfile Enable authentication against /etc/passwd-style flat files
passwd Enable /etc/passwd authentication
sha1 Use OpenSSL for sha1 encrypted passwords.
shadow Enable /etc/shadow authentication

vpopmail

clearpasswd Enables cleartext password storage in the vpasswd files
ipalias Enables enable-ip-alias-domains
maildrop Enables mail-filter/maildrop support in vdelivermail
spamassassin Enables mail-filter/spamassassin support

net-misc

AQtion

lro Enable/disable Large Receive Offload. This MUST be disabled for bridging or forwarding.

apt-cacher-ng

fuse Install the sys-fs/fuse based acngfs, to use a userspace filesystem for the apt cache.

aria2

bittorrent Enable support for the bittorrent protocol.
gnutls Use net-libs/gnutls as TLS provider (preferred). Otherwise, dev-libs/openssl will be used as TLS provider. Both apply only with USE=ssl.
libuv Use dev-libs/libuv backend.
libxml2 Use dev-libs/libxml2 for XML parsing (preferred) instead of dev-libs/expat.
metalink Enable support for metalink.
nettle Use dev-libs/nettle for message digests, plus dev-libs/gmp for bittorrent (if enabled). If this flag is disabled, dev-libs/libgcrypt is used instead. This flag is ignored if dev-libs/openssl is used.
scripts Install additional scripts which use aria2's xmlrpc functionality.
ssh Enable SFTP support.

asterisk

blocks Utlize -fblocks (only supported by, and required when using, clang/LLVM)
cluster Enable high-availability support through the Corosync Cluster Engine
codec2 Enable Codec2 support in asterisk
dahdi Support Digium compatible hardware (formerly known as Zaptel)
deprecated Enable deprecated features (eg, app_macro)
gtalk Enable support for Google Talk services
http Enable embedded web server
ilbc Enable the Internet Low Bitrate Codec (iLBC)
newt Include additional tools that require redhats windowing toolkit
pjproject Enable support for pjproject (pjsip)
span Enable support for the spandsp codec
srtp Enable support for encrypted voice transmission (secure RTP)
statsd Enable statsd integration
unbound Enable improved DNS core (SRV, NAPTR) by use of libunbound

asterisk-core-sounds

alaw Install the sounds files for the alaw codec.
g722 Install the sounds files for the g722 codec.
g729 Install the sounds files for the g729 codec.
siren14 Install the sounds files for the siren14 codec.
siren7 Install the sounds files for the siren7 codec.
sln16 Install the sounds files for the sln16 codec.
ulaw Install the sounds files for the ulaw codec.
wav Install the sounds files for the wav codec.

asterisk-extra-sounds

alaw Install the sounds files for the alaw codec.
g722 Install the sounds files for the g722 codec.
g729 Install the sounds files for the g729 codec.
gsm Install the sounds files for the gsm codec.
siren14 Install the sounds files for the siren14 codec.
siren7 Install the sounds files for the siren7 codec.
sln16 Install the sounds files for the sln16 codec.
ulaw Install the sounds files for the ulaw codec.
wav Install the sounds files for the wav codec.

asterisk-moh-opsound

alaw Install the sounds files for the alaw codec.
g722 Install the sounds files for the g722 codec.
g729 Install the sounds files for the g729 codec.
gsm Install the sounds files for the gsm codec.
siren14 Install the sounds files for the siren14 codec.
siren7 Install the sounds files for the siren7 codec.
sln16 Install the sounds files for the sln16 codec.
ulaw Install the sounds files for the ulaw codec.
wav Install the sounds files for the wav codec.

bfgminer

adl Enable support for controlling fans and overclocking on AMD cards with AMD Display Library
alchemist Enable support for mining with AlcheMist
avalon Enable support for mining with Avalon 1 ASIC modules
avalonmm Enable support for mining with Avalon 2/3 ASIC modules
bfsb Enable support for mining on BFSB host Raspberry Pi
bfx Enable support for mining with BFx2 USB sticks
bifury Enable support for mining with Bi*fury USB sticks
bigpic Enable support for mining with Big Picture Mining USB sticks (Red/BlueFury, BF1, etc)
bitforce Enable support for mining with ButterFly Labs BitFORCE ASICs and/or FPGAs
bitfury Enable support for mining with 55nm Bitfury-based devices
bitmain Enable support for mining with Bitmain Antminer S* series
cointerra Enable support for mining with CoinTerra TerraMiner.
cpumining Enable support for mining with CPUs
drillbit Enable support for mining with Drillbit boards
dualminer Enable support for mining with DualMiner USB sticks
gridseed Enable support for mining with 5-chip GridSeed orbs
hashbuster Enable support for mining with HashBuster nano boards
hashbuster2 Enable support for mining with HashBuster micro boards
hashfast Enable support for mining with HashFast devices
icarus Enable support for mining with Icarus-compatible devices (including Block Erupter Sapphire ASICs)
jingtian Enable support for mining on JingTian boards via SPI/GPIO
keccak Enable support for mining with Keccak miners
klondike Enable support for mining with Klondike USB miners
libusb Use libusb
littlefury Enable support for mining with LittleFury USB sticks
metabank Enable support for mining on Metabank host Raspberry Pi
minion Enable support for mining on minion chips via SPI (BlackArrow Prospero)
modminer Enable support for mining with ModMiner FPGAs
nanofury Enable support for mining with NanoFury USB sticks
opencl Enable support for mining with OpenCL-capable devices (GPUs)
proxy Enable support for virtual proxy device
proxy_getwork Enable proxy support for getwork protocol (often used with Block Erupter Blades)
proxy_stratum Enable proxy support for stratum protocol
rockminer Enable support for mining with RockMiner devices
screen Provide start-bfgminer.sh script to launch BFGMiner in app-misc/screen
scrypt Enable support for scrypt mining algorithm
sha256d Enable support for SHA256d mining algorithm
twinfury Enable support for mining with Twinfury USB sticks
udev-broad-rules Enable broader udev rules that may match non-mining devices
x6500 Enable support for mining with X6500 FPGAs
zeusminer Enable support for mining with ZeusMiner units
ztex Enable support for mining with Ztex FPGAs

bird

client Build the ncurses/readline full featured CLI
libssh Enables net-libs/libssh binding, mendatory for RPKI support

casync

fuse Enable fuse support

cgminer

ants1 Enable support for Antminer S1 Bitmain
ants2 Enable support for Antminer S2 Bitmain
ants3 Enable support for Antminer S3 Bitmain
avalon Enable support for Avalon ASICs
avalon-miner Enable support for Avalon miner ASICs
avalon2 Enable support for Avalon2 ASICs
avalon4 Enable support for Avalon4 ASICs
avalon7 Enable support for Avalon7 ASICs
bab Enable support for BlackArrow Bitfury
bflsc Enable support for BFL ASICs
bitforce Enable support for mining with ButterFly Labs BitFORCE FPGAs
bitfury Enable support for mining with BitFury ASICs
bitmine_A1 Enable support for mining with Bitmine.ch A1 ASICs
blockerupter Enable support for mining with BlockRupter ASICs
cointerra Enable support for mining with Cointerra ASICs
drillbit Enable support for mining with Drillbit BitFury ASICs
hashfast Enable support for mining with Hashfast
hashratio Enable support for mining with Hashratio
icarus Enable support for mining with Icarus FPGAs
klondike Enable support for mining with Klondik ASICs
knc Enable support for mining with KnC miners
minion Enable support for mining with BlackArrow Bitfury
modminer Enable support for mining with ModMiner FPGAs
sp10 Enable support for Spondoolies SP10
sp30 Enable support for Spondoolies SP30

chrony

cmdmon Support for command and monitoring
debug Get DEBUG_LOG output from chronyd when passing -dd parameter
html Install HTML documentation
libtomcrypt Support different hashes via dev-libs/libtomcrypt
nettle Use dev-libs/nettle for hash functions or nts
nss Use dev-libs/nss for hash functions
ntp Support for the Network Time Protocol (NTP)
nts Support for Network Time Security (NTS). Uses net-libs/gnutls
phc Support for the PTP (Precision Time Protocol) Hardware Clock (PHC) interface
pps Support for the Linux Pulse Per Second (PPS) interface
refclock Support for reference clocks
rtc Support for the Linux Real Time Clock interface
sechash Enable support for hashes other than MD5

connman

ethernet Enable ethernet support.
iptables Use net-firewall/iptables as firewall.
iwd Enable wifi support via net-wireless/iwd
l2tp Use net-dialup/xl2tpd for L2TP VPN support.
nftables Use net-firewall/nftables as firewall.
ofono Use net-misc/ofono for telephony support.
openconnect Use net-vpn/openconnect for VPN support.
openvpn Use net-vpn/openvpn for openvpn support.
pptp Use net-dialup/pptpclient for PPTP VPN support.
tools Enable testing tools.
vpnc Use net-vpn/vpnc for cisco VPN support.
wireguard Enable WireGuard VPN support.
wispr Enable support for WISPr hotspot logins.

connman-gtk

openconnect Support easier authentication to AnyConnect VPNs

curl

alt-svc Enable alt-svc support
ftp Enable FTP support
gnutls Enable gnutls ssl backend
gopher Enable Gopher protocol support
hsts Enable HTTP Strict Transport Security
http2 Enable HTTP/2.0 support
imap Enable Internet Message Access Protocol support
mbedtls Enable mbedtls ssl backend
nghttp3 Enable HTTP/3.0 support using net-libs/nghttp3 and net-libs/ngtcp2
nss Enable nss ssl backend
openssl Enable openssl ssl backend
pop3 Enable Post Office Protocol 3 support
progress-meter Enable the progress meter
rtmp Enable RTMP Streaming Media support
rustls Enable Rustls ssl backend
smtp Enable Simple Mail Transfer Protocol support
ssh Enable SSH urls in curl using libssh2
ssl Enable crypto engine support (via openssl if USE='-gnutls -nss')
sslv3 Support for the old/insecure SSLv3 protocol
telnet Enable Telnet protocol support
tftp Enable TFTP support
websockets Enable websockets support

dahdi

flash Support (short) flash on FXS
oslec Enable OSLEC (software) echo canceller (require ECHO in kernel)

dahdi-tools

ppp Enables PPP/DAHDIRAS support

dhcp

client Install the dhclient program
server Install the dhcpd and dhcrelay programs

dhcpcd

embedded Embed the definitions of dhcp options in the dhcpcd executable
privsep Enable support for privilege separation

dibbler

resolvconf Use resolvconf to handle /etc/resolv.conf updates

dropbear

bsdpty Add support for legacy BSD pty's rather than dynamic UNIX pty's -- do not use this flag unless you are absolutely sure you actually want it
multicall Build all the programs as one little binary (to save space)
shadow Enable shadow password support

dropbox-cli

gpg Use app-crypt/gpgme to verify signatures

electron-cash

amodem Enable plugin to support Audio Modem
cli Enables the CLI interface
cosign Enable plugin to support multisig wallets between multiple Electrum clients
digitalbitbox Enable plugin to support Digital Bitbox hardware wallet
email Enable plugin to support emailing invoices
qrcode Enable QR code scanning with media-gfx/zbar
sync Enable plugin to sync wallet metadata across multiple Electrum clients
vkb Enable plugin for virtual keyboard

electrum

cli Enables the CLI interface
qrcode Enable QR code scanning with media-gfx/zbar

electrum-ltc

cli Enables the CLI interface
qrcode Enable QR code scanning with media-gfx/zbar

etherdfs

tsr Build the TSR program for DOS, which acts as a client.

ethflop

tsr Build the TSR program for DOS, which acts as a client.

eventd

libcanberra Enable plugin for sounds via media-libs/libcanberra
libnotify Enable plugin to relay events to notification daemon (Note: not required for local notifications via net-misc/eventd)
notification Enable plugin to display on-screen notifications
purple Enable plugin for IM notifications via libpurple
speech Enable plugin for Text-To-Speech support
webhook Enable plugin to send payloads to webhook handlers
websocket Enable support for WebSocket protocol

fatrat

bittorrent Use the bittorrent protocol via net-libs/libtorrent-rasterbar.

felix

bird Use BIRD, e.g. for route reflection

freerdp

aad Enable login via Azure AD
openh264 Enable H.264 support using media-libs/openh264
server Build server binaries

frr

fpm Enable Forwarding Plane Manager support
grpc Enable gRPC plugin
nhrp Build Next Hop Resolution Protocol daemon
ospfapi Build OSPFAPI support
pam Add support for PAM (via sys-libs/pam) to the Virtual Terminal Interface Shell (vtysh)
rpki Enable RPKI

gerbera

curl Support HTTP media sources (e.g. internet radio)
exiv2 Use media-gfx/exiv2 to extract EXIF information
ffmpegthumbnailer Enable video thumbnail support with media-video/ffmpegthumbnailer
mysql Use dev-db/mysql as backend rather than SQLite3
taglib Use media-libs/taglib for reading files' metadata

gnome-remote-desktop

aac Use media-libs/fdk-aac for audio output redirection of the RDP backend

gsasl

client Build client component
gcrypt Use dev-libs/libgcrypt for low-level crypto
ntlm Add support for Microsoft's NTLM mechanism using net-libs/libntlm
server Build server component

htbinit

esfq Add support for Enhanced Stochastic Fairness queueing discipline.

hylafaxplus

html Convert faxes into html email
jbig JBIG Fax Compression Support
mgetty Receive faxes via serial port connections
pam hfaxd authentication via PAM

icaclient

hdx Install and enable hdx-realtime-media-engine plugin
usb Allow connecting USB devices to virtual desktops

icecast

kate Add karaoke and text encapsulation support for Ogg files
yp Build support for yp public directory listings

inetutils

dnsdomainname Enable domainname
ftp Enable ftp
ftpd Enable ftpd
hostname Enable hostname
ifconfig Enable ifconfig
inetd Enable inetd
logger Enable logger
ping Enable ping
ping6 Enable ping6
rcp Enable rcp
rexec Enable rexec
rexecd Enable rexecd
rlogin Enable rlogin
rlogind Enable rlogind
rsh Enable rsh
rshd Enable rshd
syslogd Enable syslogd
talkd Enable talkd
telnet Enable telnet
telnetd Enable telnetd
tftp Enable tftp
tftpd Enable tftpd
traceroute Enable traceroute
uucpd Enable uucpd
whois Enable whois

iputils

arping Build and install arping -- tool for sending ARP requests to peers (see also net-analyzer/arping)
clockdiff Build and install clockdiff -- tool for comparing clocks via ICMP packets
rarpd Build and install rarpd -- server for handling RARP (reverse ARP) requests; generally only used by old systems
rdisc Build and install rdisc -- server for the client side of the ICMP router discover protocol
tracepath Build and install tracepath -- tool for tracing network paths for discovering MTU values

kafka-bin

connect Install init for Kafka Connect Distributed mode
internal-zookeeper Use bundled local zookeeper instance

kafkacat

avro Enable avro serialization/deserialization support
json Enable json support

kea

openssl Use dev-libs/openssl instead of dev-libs/botan
samples Install sample configuration files
shell Install kea-shell text management client for Control Agent

knock

server Installs the knockd server daemon.

libteam

zmq Build witch net-libs/zeromq support

lldpd

cdp Enable Cisco Discovery Protocol
dot1 Enable Dot1 extension (VLAN stuff)
dot3 Enable Dot3 extension (PHY stuff)
edp Enable Extreme Discovery Protocol
fdp Enable Foundry Discovery Protocol
graph Create dot graphs in documentations
lldpmed Enable LLDP-MED extension
old-kernel Enable compatibility with Linux kernel older than 2.6.39
sanitizers Enable code instrumentation with selected sanitizers
snmp Enable the use of SNMP
sonmp Enable SynOptics Network Management

memcached

slabs-reassign Allow manual reassignment of memory slabs at the cost of slab optimizations.

minidlna

netgear Enable netgear branding
readynas Enable readynas branding

miniupnpd

igd2 Build for IGDv2 instead of an IGDv1
leasefile Enable lease file.
nftables Use net-firewall/nftables rather than net-firewall/iptables.
pcp-peer Enable support for PCP-PEER to allow NAT-PMP clients to mangle their packets.
portinuse Check if a port is in use before allowing a NAT-PMP client to map it.
strict Be more strict regarding compliance with UPnP specifications.

modemmanager

mbim Enable MBIM modem protocol
qmi Enable support for the QMI modem protocol used by devices with Qualcomm chipsets
qrtr Enable support for the QMI over IPC Router bus (QRTR) protocol

moonlight

cuda Enable accelerated video rendering on NVIDIA hardware
embedded Optimize UI for fullscreen non-desktop usage
glslow Prefer direct KMS/DRM rendering over EGL/GLES rendering for better performance on some weaker GPUs
libdrm Enable video rendering via x11-libs/libdrm
mmal Enable accelerated video rendering on the Raspberry Pi
soundio Enable sound output via media-libs/libsoundio instead of media-libs/libsdl2

mosh

client Build network client
examples Include example scripts
mosh-hardening Enable compiler and linker options to frustrate memory corruption exploits
nettle Use dev-libs/nettle for some cryptographic functions instead of dev-libs/openssl. With Nettle, some of mosh's own code is used for OCB.
server Build network server
ufw Install net-firewall/ufw rule set
utempter Include libutempter support

mrouted

rsrr Enable Routing Support for Resource Reservations, for RSVP

mulk

checksum Enable checksum verification for Metalink from dev-libs/openssl
metalink Enable support for media-libs/libmetalink

netifrc

dhcp Allow interfaces to configure via DHCP

netkit-bootparamd

libtirpc Build against net-libs/libtirpc for RPC support

networkmanager

concheck Enable connectivity checking support
connection-sharing Support connection sharing (uses net-dns/dnsmasq)
dhclient Use dhclient from net-misc/dhcp for getting an IP via DHCP
dhcpcd Use net-misc/dhcpcd for getting an IP
elogind Use sys-auth/elogind for session tracking
iptables Use net-firewall/iptables for connection sharing
iwd Use net-wireless/iwd instead of net-wireless/wpa_supplicant for wifi support by default
lto Build using Link Time Optimizations (LTO)
modemmanager Enable support for mobile broadband devices using net-misc/modemmanager
nftables Use net-firewall/nftables for connection sharing
nss Use dev-libs/nss for cryptography
ofono Use net-misc/ofono for telephony support.
ovs Enable OpenVSwitch support
ppp Enable support for mobile broadband and PPPoE connections using net-dialup/ppp
psl Use public suffix list via net-libs/libpsl
resolvconf Use net-dns/openresolv for managing DNS information in /etc/resolv.conf. Generally, a symlink to /run/NetworkManager/resolv.conf is simpler. On systems running systemd-resolved, disable this flag and create a symlink to /run/systemd/resolve/stub-resolv.conf.
teamd Enable Teamd control support
tools Build cli tools such as nmcli, nmtui and nm_cloud_setup
wext Enable support for the deprecated Wext (Wireless Extensions) API; needed for some older drivers (e.g. ipw2200, ndiswrapper)
wifi Enable support for wifi and 802.1x security

nextcloud-client

dolphin Install the kde-apps/dolphin extension
nautilus Install the gnome-base/nautilus extension
webengine Enable old Flow1 login using dev-qt/qtwebengine

ntp

openntpd Allow ntp to be installed alongside openntpd
parse-clocks Add support for PARSE clocks
samba Provide support for Samba's signing daemon (needed for Active Directory domain controllers)

ntpsec

early Drop root privileges early
gdb Enable debugging with gdb
heat Install contrib heat generating scripts
libbsd Use libbsd instead of internal funcs
nist Set local clock deps
ntpviz Make visualizations of offsets, jiffies, etc.
rclock_arbiter Arbiter 1088A/B GPS driver
rclock_generic Enable support for generic time radios and GPSDOs
rclock_gpsd Enable gpsd daemon support
rclock_hpgps Hewlett Packard GPS driver
rclock_jjy JJY driver
rclock_local Support for undisciplined local clock (not recommended)
rclock_modem NIST/USNO/PTB Modem Time Services
rclock_nmea NMEA GPS driver
rclock_oncore Oncore driver
rclock_pps PPS cesium clock driver
rclock_shm Obtain refclock info from shared memory-segment
rclock_spectracom Spectracom driver
rclock_trimble Trimble driver
rclock_truetime Trutime driver (deprecated)
rclock_zyfer Zyfer driver
smear Specify the interval over which a leap second is applied (experimental)

ofono

atmodem ETSI AT modem support.
bluetooth Enable Bluetooth modem support using net-wireless/bluez.
cdmamodem Enable CDMA modem support.
datafiles Enable install configuration and data files.
dundee Enable BlueTooth DUN deamon support.
isimodem Enable PhoNet/ISI modem support.
phonesim Enable phone Simulator support
provision Enable GPRS provisioning support
qmimodem Enable Qualcomm QMI modem support
tools Enable testing tools

oidentd

masquerade Enable support for masqueraded/NAT connections

olsrd

pud Install the Node Position Update plugin

openntpd

constraints Enable HTTPS TLS time constraint support

openssh

ldns Use LDNS for DNSSEC/SSHFP validation.
livecd Enable root password logins for live-cd environment.
security-key Include builtin U2F/FIDO support
ssl Enable additional crypto algorithms via OpenSSL
xmss Enable XMSS post-quantum authentication algorithm

openssh-contrib

X509 Adds support for X.509 certificate authentication
hpn Enable high performance ssh
ldns Use LDNS for DNSSEC/SSHFP validation.
livecd Enable root password logins for live-cd environment.
security-key Include builtin U2F/FIDO support
ssl Enable additional crypto algorithms via OpenSSL
xmss Enable XMSS post-quantum authentication algorithm

openvswitch

monitor Build the Python and GUI dependent monitor applications

owncloud-client

dolphin Install the kde-apps/dolphin extension
nautilus Install the gnome-base/nautilus extension

packETH

cli Build and install packETHcli

plowshare

view-captcha View captcha with aview

ps3mediaserver

multiuser Allow renderer customization per-user.
transcode Install optional dependencies for transcoding support via media-video/mplayer
tsmuxer Install optional dependencies for transcoding support via media-video/tsmuxer

ptpd

debug Enable debugging informations
experimental Enable experimental features
ntp Enable NTPD cooperation
pcap Require net-libs/libpcap to allow layer 2 (raw Ethernet) transport
slave-only Enable slave only operation (remove master mode functionality)
snmp Require net-analyzer/net-snmp to enable SNMP configuration
statistics Enable compution of statistics

putty

gssapi Enable support for GSSAPI (virtual/krb5)
gtk Build the PuTTY client which requires x11-libs/gtk+. If disabled only the CLI tools puttygen, plink, pscp and psftp will be built
gtk2 Build the PuTTY client with x11-libs/gtk+:2 instead of x11-libs/gtk+:3

r8125

multi-tx-q Enable Multiple Tx Queue ("RSS" for sending)
ptp Enable Precision Time Protocol support
rss Enable Receive Side Scaling (RSS)
use-firmware Support automatic firmware loading

r8152

center-tap-short Enable support for center tap short

r8168

use-firmware Enable support for automatic firmware loading

rdesktop

kerberos Enable CredSPP support + Kerberos authentication
pcsc-lite Enable smartcard support with sys-apps/pcsc-lite driver
xrandr Enable XRandR window extension support

remmina

gvnc Enable GVNC plugin using gtk-vnc, suitable for KVM and Vino servers
kwallet Enable KDE Wallet plugin
spice Support connecting to SPICE-enabled virtual machines
ssh Enable support for SSH/SFTP protocol

rsync

rrsync Install rrsync script to setup restricted rsync users via ssh logins
stunnel Provide helper scripts for using rsync via >=net-misc/stunnel-4
system-zlib Use system zlib instead of bundled one. This is incompatible with older rsync releases!
xxhash Enable dev-libs/xxhash support for hashing

rygel

tracker Install dependencies for the tracker plugin
transcode Install dependencies for transcoding support

scponly

chroot Enables adding and configuring an 'scponlyc' chrooted user
gftp Enables gFTP compatibility
logging Enables SFTP logging compatibility
passwd Enables passwd compatibility
quota Enables quota compatibility
rsync Enables rsync compatibility with potential security risks
scp Enables scp compatibility with potential security risks
sftp Enables SFTP compatibility
subversion Enables Subversion compatibility with potential security risks
unison Enables Unison compatibility with potential security risks
wildcards Enables wildcard processing with potential security risks
winscp Enables WinSCP 2.0 compatibility with potential security risks

seafile-client

shibboleth Build support for Shibboleth single sign-on

sipp

pcap Enable functionality to replay RTP data from a pcap file

sitecopy

rsh This allows the use of rsh (remote shell) and rcp (remote copy) for authoring websites. sftp is a much more secure protocol and is preferred.
webdav Enable WebDav (Web-based Distributed Authoring and Versioning) support. This system allows users to collaborate on websites using a web based interface. See the ebuild for an FAQ page. Enables neon as well to handle webdav support.

sks

optimize Enables bytecode optimization

smb4k

discovery Build with net-libs/kdsoap-ws-discovery-client support to discover domains and workgroups

sntpd

adjtimex Install adjtimex for the clock adjustment algorithm.

spice-gtk

gtk3 Build the spice client (spicy), requires x11-libs/gtk+:3
mjpeg Enable builtin mjpeg video decoder
policykit Enable sys-auth/polkit support for the usbredir acl helper
usbredir Use sys-apps/usbredir to redirect USB devices to another machine over TCP
webdav Support for folder-sharing between guest and client using net-libs/phodav

sshrc

mosh Install Support for mosh

streamtuner

shout Enable shoutcast plug-in.
xiph Enable xiph.org plug-in.

stunnel

stunnel3 Install the stunnel3 wrapper.

tigervnc

dri3 Build with DRI3 support
drm Build with DRM support
java Build TigerVNC Java viewer
server Build TigerVNC server
viewer Build TigerVNC viewer

tinyssh

sodium Use dev-libs/libsodium for cryptography

turbovnc

server Build the server (vncserver, Xvnc)
viewer Build the viewer (vncviewer)

uftp

server Install uftp server daemon

vde

pcap Enable the pcap-based plugin that allows creating a switch against a real interface.

wget

cookie-check Enable cookie checks via net-libs/libpsl
metalink Enable support for media-libs/libmetalink
ntlm Enable support for NTLM (Windows-based) authorization
uuid Generate UUIDs for the WARC (Web ARChive file format) using libuuid; otherwise use a simple RNG (random number generator)

wget2

gpgme Build app-crypt/gpgme backend
http2 Enable HTTP/2.0 support via net-libs/nghttp2
openssl Enable crypto support via dev-libs/openssl
psl Use public suffix list via net-libs/libpsl

whois

xcrypt Enable crypt through sys-libs/libxcrypt package

x2goserver

fuse Use net-fs/sshfs to allow shared folders

xmrig

donate Set the default donation level to 1% instead of 0
hwloc Use sys-apps/hwloc for CPU affinity support
opencl Enable OpenCL support

youtube-viewer

gtk Install the gtk3 GUI

ytfzf

minimal Skip all optional dependencies (may no longer work out-of-the-box and require custom setting up)
thumbnails Pull media-gfx/ueberzugpp or media-gfx/ueberzug for viewing thumbnails (default method when using -t)

zerotier

sso Enable support for Single sign-on through zeroidc

net-nds

389-ds-base

accountpolicy Enable account policy plugin - automatically lock an account after a certain amount of time has elapsed
auto-dn-suffix Enable auto bind with auto dn suffix over unix domain socket (LDAPI) support
autobind Enable auto bind over unix domain socket (LDAPI) support
bitwise Enable bitwise plugin - supported data in raw/bitwise format
dna Enable dna (distributed numeric assignment ) plugin - to automatically assign unique uid numbers to new user entries as they are created.
ldapi Enable LDAP over unix domain socket (LDAPI) support
pam-passthru Enable pam-passthru plugin - for simple and fast system services used in ldap

ldapvi

gnutls Use net-libs/gnutls instead of dev-libs/openssl

nsscache

nsscache Depend on sys-auth/libnss-cache to handle flat files
s3 Support for S3-based NSS sources

openldap

argon2 Enable password hashing algorithm from app-crypt/argon2
autoca Automatic Certificate Authority overlay
cleartext Enable use of cleartext passwords
experimental Enable experimental backend options
kinit Enable support for kerberos init
minimal Build libraries & userspace tools only. Does not install any server code
odbc Enable ODBC and SQL backend options
overlays Enable contributed OpenLDAP overlays
pbkdf2 Enable support for pbkdf2 passwords
sha2 Enable support for pw-sha2 password hashes
smbkrb5passwd Enable overlay for syncing ldap, unix and lanman passwords

rpcbind

remotecalls Enable remote calls
warmstarts Enables rpcbind to cache configuration for warm restarts

tac_plus

finger Adds support for checking user counts via fingering the NAS
maxsess Enforce a limit on maximum sessions per user

net-news

rssguard

qt6 Build with Qt6 support instead of the default Qt5
webengine Use dev-qt/qtwebengine for embedded web browser

sfeed

theme-mono Use mono theme
theme-mono-highlight Use mono_highlight theme
theme-newsboat Use newsboat theme
theme-templeos Use templeos theme

net-nntp

nzbget

parcheck Enable support for checking PAR archives

slrn

canlock Add support for cancel locks via net-libs/canlock
uudeview Add support for yEnc coding and more using dev-libs/uulib

tin

cancel-locks Enable Cancel-Lock header functionality
gpg Enable app-crypt/gnupg support
libtls Prefer dev-libs/libretls as SSL/TLS provider (ineffective with USE=-ssl)

net-p2p

airdcpp-webclient

nat-pmp Enable support for the NAT-PMP protocol
tbb Enable support of the TBB library to improve performance
webui Enable the Web UI

amule

daemon Enable amule daemon
remote Enable remote controlling of the client
stats Enable statistic reporting

bitcoin-core

asm Enable assembly for optimization
berkdb Support legacy wallets in Berkeley DB format
bitcoin-cli Build and install bitcoin-cli command line interface
daemon Build and install bitcoind daemon
external-signer Include support for external wallet signer programs
gui Build and install Bitcoin-Qt GUI
libs Build and install libbitcoinconsensus
nat-pmp Enable NAT-PMP port forwarding
qrcode Enable generation of QR Codes for receiving payments
sqlite Support descriptor wallets in SQLite format
system-leveldb Link with virtual/bitcoin-leveldb rather than embedding an internal copy
system-libsecp256k1 Link with dev-libs/libsecp256k1 rather than embedding an internal copy
systemtap Enable SystemTAP/DTrace tracing
upnp Enable Universal Plug and Play
zeromq Report blocks and transactions via zeromq

bitcoin-qt

asm Enable assembly for optimization
external-signer Include support for external wallet signer programs
nat-pmp Enable NAT-PMP port forwarding
qrcode Enable generation of QR Codes for receiving payments
systemtap Enable SystemTAP/DTrace tracing
upnp Enable Universal Plug and Play
wallet Enable wallet support
zeromq Report blocks and transactions via zeromq

bitcoind

asm Enable assembly for optimization
external-signer Include support for external wallet signer programs
nat-pmp Enable NAT-PMP port forwarding
systemtap Enable SystemTAP/DTrace tracing
upnp Enable Universal Plug and Play
wallet Enable wallet support
zeromq Report blocks and transactions via zeromq

dbhub

switch-user Enable support for switching user

deluge

console Enable default console UI
webinterface Install dependencies needed for the web interface

eiskaltdcpp

cli Enable sample cli based on readline
daemon Enable eiskaltdcpp-daemon
dht Enable DHT (distributed hash table) support for libeiskaltdcpp
gold Use gold.ld instead of ld
libcanberra Enable sound notifications support over libcanberra in EiskaltDC++ Gtk
minimal Don't install headers

fms

frost Add support for frost boards
ssl Add support for FCP connection over SSL

freenet

nss Use nss for crypto operations, if it is the fastest way

go-ethereum

devtools Build Ethereum development tools (evm, abigen, puppeth, ...)

ktorrent

bwscheduler Schedule upload and download limits over a period of a week
downloadorder Specify the download order of a multi-file torrent
infowidget Displays general information about a torrent in several tabs
ipfilter Filter IP addresses through a blocklist
logviewer Displays the logging output
magnetgenerator Generates magnet URI's
mediaplayer Phonon-based media player
rss Syndication plugin for KTorrent, supporting RSS and Atom feeds
scanfolder Scan folders for torrent files and load them
shutdown Shutdown when done
stats Shows statistics about torrents in several graphs
upnp Forward ports using UPnP
webengine Embedded search for torrents using dev-qt/qtwebengine
zeroconf Discover peers on the local network using the Zeroconf protocol

mldonkey

bittorrent enable bittorrent support
fasttrack enable fasttrack support
gnutella enable gnutella and gnutella2 support
guionly enable client build only

qbittorrent

webui Install qBittorrent Web UI (qbittorrent-nox) and systemd/OpenRC service

retroshare

cli Enables terminal login support for retroshare-service
jsonapi Enables the new RetroShare JSON API
libupnp Enables UPnP port forwarding via net-libs/libupnp
miniupnp Enables UPnP port forwarding via net-libs/miniupnpc
service Enables the new RetroShare service
sqlcipher Enables GXS database encryption via SQLCipher

syncthing

tools Install stdiscosrv, strelaysrv and other tools to /usr/libexec/syncthing/.

transmission

cli Build command-line client
debug Enable assertions
lightweight Optimize transmission for low-resource systems (smaller cache size, prefer unencrypted peer connections, etc.)
mbedtls Use mbed TLS instead of OpenSSL

transmission-remote-gtk

libproxy Use net-libs/libproxy for getting the HTTP/HTTPS/SOCKS proxy configuration.

net-print

cups

openssl Use dev-libs/openssl instead of net-libs/gnutls for TLS support

cups-filters

foomatic Build the included foomatic-rip printer driver. Strongly recommended.
pclm Enable PCLm support

dymo-cups-drivers

usb-modeswitch Include usb_modeswitch for some hardware (bug #601242)

fax4cups

efax Install net-misc/efax backend
hylafax Install net-misc/hylafax backend
mgetty-fax Install net-dialup/mgetty backend

hplip

X Enables scanner GUI dependencies with USE="scanner" where media-gfx/xsane is preferred over media-gfx/sane-frontends
fax Enable fax on multifunction devices which support it
hpcups Build the hpcups driver for cups (by HP)
hpijs Build the IJS driver for cups (Foomatic)
kde Enables kde-misc/skanlite as scanner GUI with USE="scanner X"
libusb0 Depend on virtual/libusb SLOT 0. Some old printers do not work with virtual/libusb SLOT 1.
minimal Only build internal hpijs/hpcups driver (not recommended at all, make sure you know what you are doing)
parport Enable parallel port for devices which require it
scanner Enable scanner on multifunction devices which support it
snmp Add support for net-analyzer/net-snmp which enables this driver to work over networks (both for server and client)
static-ppds Use statically-generated PPDs instead of Dynamic PPDs. Although this is deprecated some printers may still need it to work properly. Use this flag if hp-setup fails to find/create a valid PPD file

hplip-plugin

orblite Install the ORBlite scanner plugin

kyocera-1x2x-mfp-driver

rastertokpsl-fix Use custom wrapper script to sanitize arguments before passing to 'rastertokpsl' filter program

net-proxy

haproxy

51degrees Device Detection using 51 Degrees
net_ns Enable network namespace support (CONFIG_NET_NS)
pcre-jit Use JIT support for PCRE
prometheus-exporter Also build the prometheus exporter
slz Use dev-libs/libslz compression library
tools Install additional tools (halog, iprange)
wurfl Device Detection using WURFL

privoxy

brotli Decompress brotli compressed data using app-arch/brotli before filtering
client-tags Enable support for client-specific tags
compression Allow privoxy to compress buffered content before sending to the client, if it supports it
editor Enable the web-based actions file editor
extended-host-patterns Enable and require PCRE syntax in host patterns. You must convert action files to PCRE, see privoxy-url-pattern-translator.pl (see tools USE flag). Use at your own risk!
extended-statistics Gather extended statistics
external-filters Allow to filter content with scripts and programs. Experimental
fast-redirects Support fast redirects
force Allow single-page disable (force load)
fuzz Exposes Privoxy internals to input from files or stdout. Intended for fuzzing testing
graceful-termination Allow to shutdown Privoxy through the webinterface
image-blocking Allows the +handle-as-image action, to send "blocked" images instead of HTML
jit Enable PCRE jit (recommended)
lfs Support large files (>2GB) on 32-bit systems
mbedtls Use net-libs/mbedtls for HTTPS filtering
openssl Use dev-libs/openssl for HTTPS filtering
png-images Use PNG format instead of GIF for built-in images
sanitize Enable asan, msan and usan sanitizers. Your compiler must support them
ssl HTTPS inspection support. Enables privoxy to perform SSL MITM filtering, see docs, use with care
stats Keep statistics
threads Enable POSIX threads. Highly recommended, otherwise both build and run-time features may not work properly.
toggle Support temporary disable toggle via web interface
tools Install log parser, regression tester and user agent generator tools
whitelists Support trust files (white lists)
zlib Decompress zlib compressed data using sys-libs/zlib before filtering

rejik

banlists Install upstream provided simple banlists

squid

ecap Adds support for loadable content adaptation modules (http://www.e-cap.org)
esi Enable ESI for accelerators, will cause squid reverse proxies to be capable of the Edge Acceleration Specification (www.esi.org)
htcp Enable HTCP protocol
logrotate Use app-admin/logrotate for rotating logs
qos Adds support for Quality of Service using netfilter conntrack - see qos_flow directive for more info
ssl-crtd Adds support for dynamic SSL certificate generation in SslBump environments
tproxy Enables real Transparent Proxy support for Linux Netfilter TPROXY
wccp Enable Web Cache Coordination Protocol
wccpv2 Enable Web Cache Coordination V2 Protocol

tinyproxy

filter-proxy Enable filtering of domains/URLS
reverse-proxy Enable reverse proxying
transparent-proxy Enable transparent proxying
upstream-proxy Enable upstream proxying
xtinyproxy-header Include the X-Tinyproxy header

trojan

mysql build with MySQL support

tsocks

dns Force DNS queries to use SOCKS server via tcp
envconf Allow TSOCKS_CONF_FILE to specify configuration file
server-lookups Allow hostname resolution _for_ SOCKS servers
tordns Apply tordns patch which allows transparent TORification of the DNS queries

net-voip

mumble

g15 Enable support for the Logitech G15 LCD (and compatible devices).
pipewire Enable pipewire support for audio output.
rnnoise Enable alternative noise suppression option based on RNNoise.
speech Enable text-to-speech support in Mumble.

murmur

grpc Use net-libs/grpc to enable remote control capabilities.
ice Use dev-libs/Ice to enable remote control capabilities.

telepathy-gabble

jingle Enable voice calls for jabber
plugins Enable plugin loader

umurmur

mbedtls Use net-libs/mbedtls as TLS provider
shm Enable shared memory support

yate

amrnb use AMR-NB
dahdi Enable Dahdi driver
gsm use GSM codec
ilbc Enable iLBC codec
ilbc-webrtc Enable iLBC webrtc codec
isac-fixed Enable iSAC fixed codec
isac-float Enable iSAC float codec
mysql use MySQL client library
postgres use Postgress SQL
spandsp use spandsp library
speex use Speex codec
tdmcard Enable TDMV API card driver
wanpipe Enable Wanpipe support
wpcard Enable Wanpipe card driver
zaptel Enable Zaptel driver

net-vpn

eduvpn-common

openvpn enable support for OpenVPN
wireguard enable support for WireGuard

i2pd

i2p-hardening Compile with hardening on vanilla compilers/linkers

libreswan

dnssec Use DNSSEC resolver (requires net-dns/unbound)

networkmanager-sstp

gtk4 Use gui-libs/gtk for GUI support.

networkmanager-strongswan

gtk4 Use GTK4 instead of GTK3.

ocserv

otp Enable support for one-time passwords

openconnect

gssapi Build GSSAPI support
libproxy Enable proxy support
pskc Enable PSKC file storage of HOTP/TOTP keys
stoken Enable stoken support

openvpn

dco Enable support for kernel data channel offload
down-root Enable the down-root plugin
iproute2 Enabled iproute2 support instead of net-tools
mbedtls Use mbed TLS as the backend crypto library
openssl Use OpenSSL as the backend crypto library
pkcs11 Enable PKCS#11 smartcard support
plugins Enable the OpenVPN plugin system

ovpn-dco

debug Enable debug output in dmesg

pptpd

gre-extreme-debug Log all GRE accepted packets when in debug mode (required if you want upstream support)

strongswan

constraints Enable advanced X.509 constraint checking plugin
dhcp Enable server support for querying virtual IP addresses for clients from a DHCP server. (IKEv2 only)
eap Enable support for the different EAP modules that are supported
farp Enable faking of ARP responses for virtual IP addresses assigned to clients (IKEv2 only)
gcrypt Enable dev-libs/libgcrypt plugin which provides 3DES, AES, Blowfish, Camellia, CAST, DES, Serpent and Twofish ciphers along with MD4, MD5 and SHA1/2 hash algorithms, RSA and DH groups 1,2,5,14-18 and 22-24(4.4+). Also includes a software random number generator.
non-root Force IKEv1/IKEv2 daemons to normal user privileges. This might impose some restrictions mainly to the IKEv1 daemon. Disable only if you really require superuser privileges.
openssl Enable dev-libs/openssl plugin which is required for Elliptic Curve Cryptography (DH groups 19-21,25,26) and ECDSA. Also provides 3DES, AES, Blowfish, Camellia, CAST, DES, IDEA and RC5 ciphers along with MD2, MD4, MD5 and SHA1/2 hash algorithms, RSA and DH groups 1,2,5,14-18 and 22-24(4.4+) dev-libs/openssl has to be compiled with USE="-bindist".
pkcs11 Enable pkcs11 support
strongswan_plugins_addrblock Enable support for the addrblock crypto plugin
strongswan_plugins_aesni Enable support for Intel AES-NI crypto plugin
strongswan_plugins_blowfish Enable support for the blowfish plugin
strongswan_plugins_bypass-lan Enable support for the bypass-lan plugin
strongswan_plugins_ccm Enable support for the ccm plugin
strongswan_plugins_chapoly Enable ChaCha20/Poly1305 AEAD implementation and ChaCha20 XOF plugin
strongswan_plugins_ctr Enable support for the ctr plugin
strongswan_plugins_error-notify Enable support for the error-notify plugin
strongswan_plugins_forecast Enable multicast and broadcast forwarding plugin
strongswan_plugins_gcm Enable support for the gcm plugin
strongswan_plugins_ha Enable support for the ha plugin
strongswan_plugins_ipseckey Enable support for the ipseckey plugin
strongswan_plugins_kdf Enable support for the kdf plugin
strongswan_plugins_led Enable support for the led plugin
strongswan_plugins_lookip Enable support for the lookip plugin
strongswan_plugins_newhope Enable plugin that allows key exchange based on post-quantum computer New Hope algorithm
strongswan_plugins_ntru Enable support for the ntru plugin
strongswan_plugins_padlock Enable support for the padlock plugin
strongswan_plugins_rdrand Enable support for the rdrand plugin
strongswan_plugins_save-keys Enable plugin that saves IKE and/or ESP keys to files compatible with Wireshark (for debugging)
strongswan_plugins_systime-fix Enable support for the systime-fix plugin
strongswan_plugins_unbound Enable support for the unbound plugin
strongswan_plugins_unity Enable support for the unity plugin
strongswan_plugins_vici Enable support for the vici plugin
strongswan_plugins_whitelist Enable support for the whitelist plugin
strongswan_plugins_xauth-noauth Enable support for the xauth-noauth plugin

tinc

uml Enable support for User Mode Linux Sockets
vde Enable Virtual Distributed Ethernet (VDE) based networking

tor

scrypt Use app-crypt/libscrypt for the scrypt algorithm
server Enable tor's relay module so it can operate as a relay/bridge/authority
tor-hardening Compile tor with hardening on vanilla compilers/linkers

vpnc

resolvconf Enable support for DNS managing framework net-dns/openresolv

wireguard-modules

debug Enable verbose debug reporting in dmesg of various WireGuard peer and device information.
module Compile the actual WireGuard kernel module. Most certainly you want this enabled, unless you're doing something strange.
module-src Install the module source code to /usr/src, in case you like building kernel modules yourself.

wireguard-tools

wg-quick Install the wg-quick(8) helper tool. Most users want to use this.

net-wireless

aircrack-ng

airdrop-ng Build airdrop-ng
airgraph-ng Build airgraph-ng
experimental Build the "experimental" tools which may randomly fail to run properly
netlink Use netlink for channel control instead of WEXT

bladerf

tecla use libtecla for command line editing, tab completion, and history

bladerf-fpga

x115 bitstream for the x115 kLE Cyclone IV FPGA bladerf model"
x40 bitstream for the x40 kLE Cyclone IV FPGA bladerf model"
xA4 bitstream for the xA4 49 kLE Cyclone V FPGA bladerf 2.0 micro model"
xA9 bitstream for the xA9 301 kLE Cyclone V FPGA bladerf 2.0 micro model"

blueman

network Add functionality to setup (host) PAN connections using either net-dns/dnsmasq or net-misc/dhcp

bluez

btpclient Enable BTP client
deprecated Build deprecated plugins
experimental Build experimental plugins
extra-tools Install tools that upstream doesn't install on purpose by default. All this tools shouldn't be used. Then, please notify upstream about you still need them to let them know the situation.
mesh Add support for Bluetooth Mesh control application and advertising bearer.
midi Enable MIDI support
obex Enable OBEX transfer support
test-programs Install tools for testing of various Bluetooth functions

crda

gcrypt Use libgcrypt instead of openssl for key checking

dump1090

bladerf Build with Nuand BladeRF support
hackrf Build with Great Scott Gadgets HackRF support
minimal Exclude all HTML/webserver extras for a tiny build, e.g. to export data only
rtlsdr Build with Realtek RTL2832U (rtlsdr) support

gnome-bluetooth

sendto Build the bluetooth-sendto application to send files to various locations/devices

gnuradio

analog enable analog signal processing blocks
audio enable blocks to connect to audio sources (mic-in) and sinks (speaker-out) ports on a computer
channels enable channel mode blocks
ctrlport enable control port interface
digital enable digital signal processing blocks
dtv enable digital tv signal processing blocks
fec enable block for convolutional encoding using the CCSDS standard polynomial ("Voyager")
filter enable filter signal processing blocks
grc enable GNU Radio Companion graphical tool to design signal processing flow graphs
iio enable enable support for IIO devices
modtool enable modtool for editing GNU Radio modules and components
network enable block for networking support
performance-counters enable block performance counters
soapy enable support for SoapySDR blocks
trellis enable trellis blocks for FSM
uhd install UHD source and sink blocks
utils install scripts to enable viewing and analysis of files produced by flow graphs
vocoder enable blocks for audio voice encoders
wavelet enable wavelet signal processing blocks
zeromq enable zeromq message passing blocks

gqrx

gr-audio Use audio support from net-wireless/gnuradio

gr-osmosdr

airspy Build with Airspy support through net-wireless/airspy
bladerf Build with Nuand BladeRF support through net-wireless/bladerf
hackrf Build with Great Scott Gadgets HackRF support through net-libs/libhackrf
iqbalance Enable support for I/Q balancing using gr-iqbal through net-wireless/gr-iqbal
rtlsdr Build with Realtek RTL2832U support through net-wireless/rtl-sdr
sdrplay Enable support for SDRplay devices through net-wireless/sdrplay
soapy Build with SoapySDR support through net-wireless/soapysdr
uhd Build with Ettus Research USRP Hardware Driver support through net-wireless/uhd
xtrx Build with xtrx Hardware Driver support through net-wireless/libxtrx

horst

pcap Add support for network packet capture via net-libs/libpcap

hostapd

crda Add CRDA support
internal-tls Use internal TLSv1 implementation instead of depending on OpenSSL or GnuTLS
netlink Adding support for using netlink to create VLANs
suiteb Adding support for NSA Suite B Cryptography
wps Add support for Wi-Fi Protected Setup

iwd

client Enable iwctl client tool
crda Use net-wireless/crda for regulatory domain loading instead of in-kernel (4.15+) support
monitor Enable iwmon monitor tool
ofono Enable support for oFono SIM authentication
standalone Enable standalone mode with built-in DHCP client and DNS handling"
systemd Use systemd-resolve rather than resolvconf for DNS handling in standalone mode
wired Enable ethernet authentication daemon

kismet

libusb Support libusb based capture sources such as mousejack, cc2540(ble), and nrf51822(ble)
mqtt Enable MQTT support
pcre Build with pcre support
rtlsdr Enable rtlsdr based kismet capture sources
suid Install a setuid root helper binary with limited functionality; this allows running kismet as a normal user, significantly reducing security risks
ubertooth Enable capture source for ubertooth to sniff bluetooth low energy

libxtrxll

usb3380 support xtrx usb model

neard

tools Build and install 'nfctool' for further NFC debugging

rtl-sdr

zerocopy may cause a bus error on some ARM systems

rtl_433

rtlsdr Build with Realtek RTL2832U (rtlsdr) support
soapysdr Build with SoapySDR support

soapysdr

bladerf Add support for bladerf hardware
hackrf Add support for hackrf hardware
plutosdr Add support for Analog Devices ADALM-PLUTO hardware
rtlsdr Add support for rtlsdr hardware
uhd Add support for Ettus USRP hardware

ubertooth

bluez use bluez to support clock following and scanning
ubertooth1-firmware Build/install ubertooth1-firmware

uhd

b100 support B100 hardware
b200 support B200, B210, B200mini, B205mini hardware
e300 support E300, E310 hardware
mpmd support N300, N310 hardware
octoclock Octoclock Network Support
usrp1 support USRP1 hardware
usrp2 support USRP2, N200, N210 hardware
utils utilities needed to list, query, calibrate, or update FPGA/Firmware
x300 support X300, X310 hardware

unifi

system-mongodb Using dev-db/mongodb systemd service instead of the bundled one

urh

airspy use native backend which directly uses net-wireless/airspy
audio use a soundcard instead of an sdr
bladerf use native backend which directly uses net-wireless/bladerf
hackrf use native backend which directly uses net-libs/libhackrf
limesdr use native backend which directly uses net-wireless/limesuite
plutosdr use native backend which directly uses net-libs/libiio
rtlsdr use native backend which directly uses net-wireless/rtl-sdr
sdrplay use native backend which directly uses net-wireless/sdrplay
uhd use native backend which directly uses net-wireless/uhd

wepattack

john Build with app-crypt/johntheripper support

wireless-regdb

crda Use obsolete net-wireless/crda for regulatory domain loading instead of in-kernel (4.15+) support

wireless-tools

multicall Build the most commonly used tools as one binary

wpa_supplicant

ap Add support for access point mode
broadcom-sta Flag to help users disable features not supported by broadcom-sta driver
crda Use net-wireless/crda for regulatory domain loading instead of in-kernel (4.15+) support
eap-sim Add support for EAP-SIM authentication algorithm
eapol-test Build and install eapol_test binary
fasteap Add support for FAST-EAP authentication algorithm
fils Add support for Fast Initial Link Setup (802.11ai)
hs2-0 Add support for 802.11u and Passpoint for HotSpot 2.0
macsec Add support for wired macsec
mbo Add support Multiband Operation
mesh Add support for mesh mode
p2p Add support for Wi-Fi Direct mode
privsep Enable wpa_priv privledge separation binary
ps3 Add support for ps3 hypervisor driven gelic wifi
smartcard Add support for smartcards
tdls Add support for Tunneled Direct Link Setup (802.11z)
tkip Add support for WPA TKIP (deprecated due to security flaws in 2009)
uncommon-eap-types Add support for GPSK, SAKE, GPSK_SHA256, IKEV2 and EKE
wep Add support for Wired Equivalent Privacy (deprecated due to security flaws in 2004)
wimax Add support for Wimax EAP-PEER authentication algorithm
wps Add support for Wi-Fi Protected Setup

sci-astronomy

cpl

gasgano Enable support for sci-astronomy/gasgano file organizer

esomidas

libtirpc Build against net-libs/libtirpc for RPC support

kstars

fits Enable support for NASA's sci-libs/cfitsio library
indi Enable support for Astronomical control library using libindi
password Store passwords securely via dev-libs/qtkeychain
wcs Enable support for World Coordinate System library using wcslib

predict

xforms Add a "map" client which uses the x11-libs/xforms library for its GUI
xplanet Project predict data onto world maps generated by x11-misc/xplanet / x11-misc/xearth

psfex

plplot Build with sci-libs/plplot to allow diagnostic plots during processing

scamp

plplot Build with sci-libs/plplot to allow diagnostic plots during processing

sextractor

modelfit Enable profile model fitting, needs sci-libs/atlas and sci-libs/fftw

siril

libconfig Require dev-libs/libconfig to read old configuration files
wcs Add supprt astrometry features using sci-astronomy/wcslib

stellarium

deep-sky Install extra deep sky objects catalog (may affect performance)
media Enable sound and video support
scripting Enable JS scripting via dev-qt/qtscript in Qt5 or using Qml via dev-qt/qtdeclarative in Qt6
show-my-sky Enable a better atmosphere model via sci-astronomy/calcmysky
stars Install extra star catalogs
telescope Enable telescope control via sci-libs/indilib
webengine Show online results about the selected star in an embedded window using dev-qt/qtwebengine
xlsx Support XLSX (Excel) files via dev-libs/qxlsx

swarp

cfitsio Link with sci-libs/cfitsio

wcslib

fits Enable support for the FITS format through sci-libs/cfitsio
pgplot Builds PGBSOX routines, needs sci-libs/pgplot library
tools Builds and installs extra command line utilities for WCS checking

sci-biology

abyss

misc-haskell build abyss-samtobreak tool, pull in haskell toolchain

bioperl

db Install sci-biology/bioperl-run
network Install sci-biology/bioperl-run
run Install sci-biology/bioperl-run

clustalw-mpi

mpi-njtree Use MPI (as opposed to serial) code for computing neighbor-joining trees
static-pairalign Use static (as opposed to dynamic) scheduling for pair alignments

exonerate

utils Install the follow binaries: esd2esi, fasta2esd, fastaannotatecdna, fastachecksum, fastaclean, fastaclip, fastacomposition, fastadiff, fastaexplode, fastafetch, fastahardmask, fastaindex, fastalength, fastanrdb, fastaoverlap, fastareformat, fastaremove, fastarevcomp, fastasoftmask, fastasort, fastasplit, fastasubseq, fastatranslate, fastavalidcds

fasttree

double-precision use double precision instead of single-precision floating point (2x memroy required)

mcl

blast Add support for NCBI BLAST data

newick-utils

xml Uses dev-libs/libxml2 to handle ornaments

ucsc-genome-browser

server Install genome browser Web application. If this flag is off, only libraries and utilities from the suite are installed.

yass

dmalloc Enable debugging with the dmalloc library
lowmem Build for environments with low amounts of memory

sci-calculators

datamash

linux-crypto Use Linux kernel cryptographic API
openssl Use dev-libs/openssl for hash routines instead of internal gnulib

units

units-cur Install the units_cur python script that updates currencies

sci-chemistry

avogadro2

rpc Enable RPC server
vtk include vtk support

chemtool

emf EMF export support

gnome-chemistry-utils

gnumeric Add a Gnumeric plugin to provide a molarmass function for the spreadsheet

gromacs

build-manual Build manual instead of downloading it
clang Build gromacs with Clang instead of default compiler
clang-cuda Use clang for cuda units compilation
cuda Enable cuda non-bonded kernels
double-precision More precise calculations at the expense of speed
gmxapi Add support for gmxapi library
gmxapi-legacy Enable installing lagacy headers
hwloc Enable HWLoc lib support
lmfit Use external sci-libs/lmfit
mkl Use sci-libs/mkl for fft, blas, lapack routines
offensive Enable gromacs partly offensive quotes
opencl Enable opencl non-bonded kernels
single-precision Single precision version of gromacs (default)
tng Enable new trajectory format - tng

molequeue

client Build the client application
server Build the serve application
zeromq Build with net-libs/zeromq support

mopac7

gmxmopac7 Add support library for gromacs

openbabel

inchi Build support for IUPAC International Chemical Identifier format
json Build support for JSON formats (ChemDoodle, PubChem, etc...)

pymol

web Install Pymodule needed for web app support

raster3d

gd libgd support for PNG and JPEG output

vmd

cuda Use nvidia cuda toolkit for speeding up computations
gromacs Add support for TNG file format
msms Add support for MSMS SES calcualtion tool
povray Add support for povray raytracer for HQ images
tachyon Add support for tachyon raytracer for HQ images

votca

gromacs Add support for gromacs file formats through sci-chemistry/gromacs

sci-electronics

geda

stroke enable mouse gesture support

gerbv

unit-mm Set default unit for coordinates in status bar to mm

ghdl

llvm Build LLVM code generator

gspiceui

schematics Use sci-electronics/geda for schematics editing
waveform Use sci-electronics/gwave for waveform display

gtkwave

fasttree Enables experimental Fast SST Tree widget code.
fatlines Renders lines as double width in gtkwave.
judy Enables Judy array support.
packed Enables '#pragma pack' for data arrays (saves memory, costs time).

kicad

ngspice Enable circuit simulation

kicad-meta

minimal Do not install extra data like 3D packages and templates.

ktechlab

gpsim Enable support for Microchip PIC microcontrollers similation using dev-embedded/gpsim

librepcb

opencascade Build with sci-libs/opencascadethe 3D features (e.g. reading/writing STEP files)

ngspice

deprecated Build old and deprecated apps
shared Build ngspice as a shared library

nvc

jit Enable experimental JIT complilation with LLVM
llvm Build LLVM code generator

pcb

gcode gcode file export
gif GIF graphics export
gsvit GSvit file export
jpeg JPEG graphics export
m4lib-png Enable creating png previews for the m4 library
nelma NELMA file export
png PNG graphics export
tk Build tcl/tk graphical QFP footprint generator
toporouter Build toporouter

pulseview

decode Enable decoding of protocols while capturing

sigrok-cli

decode Enable decoding of protocols while capturing

splat

hires Builds additional high resolution application 'rfsplat-hd'

sci-geosciences

gmt

gdal Enable sci-libs/gdal library support
geos Enable sci-libs/geos library support
gmttria Non GNU triangulation method, more efficient

gpsd

dbus export gpsd data over dbus connections
latency-timing support latency timing information
ntp Enable net-misc/ntp shared memory interface and PPS kernel support for GPS time
shm export gpsd over shared memory
sockets export gpsd over unix sockets

grass

geos Use sci-libs/geos for v.buffer and adds extended options to the v.select module
las Include support for LAS and LAZ encoded LiDAR files through sci-geosciences/liblas
opencl Enable OpenCL support
pdal Enable support for PDAL for point clouds via sci-libs/pdal

gshhs

data Add earth data with sci-geosciences/gshhs-data

liblas

gdal Add support for the sci-libs/gdal geospatial raster library

mapserver

apache Enable mapserver to run under apache
geos Enable sci-libs/geos library support
postgis Enable dev-db/postgis support

merkaartor

libproxy Use net-libs/libproxy for getting the HTTP/HTTPS/SOCKS proxy configuration
webengine Enable dev-qt/qtwebengine in some plugins

owntracks-recorder

crypt Enable support for payload encryption with dev-libs/libsodium
greenwich Enable support for the OwnTracks Greenwich firmware
http Enable support for the built-in HTTP REST API
kill Enable support removing data via the API (dangerous)
lua Enable support for Lua hook integration
mqtt Enable MQTT support
ping Enable support for the "pingping" monitoring feature
tours Enable recorder support for shared views

qgis

3d Build QGIS 3D library using dev-qt/qt3d
georeferencer Determines whether georeferencer plugin should be built
grass Add support for grass
hdf5 Enable MDAL support for sci-libs/hdf5
mapserver Determines whether mapserver should be built
netcdf Enable MDAL support for GRIB and XMDF formats
opencl Enable OpenCL support
pdal Enable support for PDAL for point clouds via sci-libs/pdal
polar Enable support for the polar coordinate system via x11-libs/qwtpolar
qml Enable support Qml-based plugins using dev-qt/qtdeclarative
serial Enable support for serial GPS using dev-qt/qtserialport

viking

geoclue Use app-misc/geoclue to determine current location
libexif Use media-libs/libexif for EXIF support
oauth Enable OAuth authentication for OSM

sci-libs

ViSP

coin Enables Coin3D support.
demos Installs demo programs.
dmtx Enables barcode data matrix support.
ogre Enables dev-games/ogre support.
opencv Enables media-libs/opencv support.
pcl Enables sci-libs/pcl support.
tutorials Installs tutorials.
zbar Enables barcodes reading.

XNNPACK

assembly Build with assembly micro-kernels
jit Build with JIT micro-kernels
memopt Build with optimized memory allocation scheme
sparse Build with graph rewriting for sparse inference

adolc

boost Use the boost allocator from dev-libs/boost
sparse Add support for sparse matrix algebra with sci-libs/colpack

armadillo

arpack Link with sci-libs/arpack libraries for eigen decomposition
mkl Use matrix allocation from the Intel MKL sci-libs/mkl
superlu Use SuperLU for sparse linear equation solving sci-libs/superlu

arprec

qd Use sci-libs/qd for quad-double datatype

atlas

generic Build atlas assuming a fairly generic architecture (sse2 for x86, core2 for amd64)

avogadrolibs

archive Enable archive support using app-arch/libarchive
vtk Enable sci-libs/vtk support

blis

64bit-index Enable 64bit array indexing, incompatible with runtime switching
eselect-ldso Enable runtime library switching by eselect and ld.so.
openmp Use openmp threadding model
pthread Use pthread threadding model
serial Use no threadding model

caffe2

cuda Add support for CUDA processing
distributed Support distributed applications
fbgemm Use FBGEMM
ffmpeg Add support for video processing operators
gloo Use sci-libs/gloo
nnpack Use NNPACK
numpy Add support for math operations through numpy
opencl Use OpenCL
opencv Add support for image processing operators
openmp Use OpenMP for parallel code
qnnpack Use QNNPACK
tensorpipe Use tensorpipe
xnnpack Use XNNPACK

cantera

cti Install conversion tools (ck2cti, ck2yaml, ctml_writer) from Chemkin to Cantera format
hdf5 Add HDF5 container files support
python Install Python bindings and conversion tools from Chemkin to Cantera format

cddlib

tools Add a few executables and tests for cddlib

ceres-solver

cxsparse Enable simple support for sparse matrix algebra from sci-libs/cxsparse with no LAPACK dependencies
gflags Use dev-cpp/gflags for flag parsing
schur Enable fixed-size schur specializations (disable if binary size is an issue)
sparse Enable support for sparse matrix algebra with various packages from SuiteSparse

cfitsio

tools Build optional utilities (cookbook fitscopy imcopy smem speed testprog fpack funpack)

cgnslib

base-scope Enable base scoped families or connectivities
legacy Enable or disable building legacy code (3.0 compatible)
scoping Enable scoping of enumeration values
tools A number of utility programs: cgnscheck, cgnscompress, cgnsdiff, cgnslist, cgnsnames, cgnsupdate, cgnsconvert, adf2hdf, hdf2adf.

cholmod

cholesky Enable sparse Cholesky factorisation
cuda Use nvidia cuda toolkit for speeding up computations
matrixops Support basic sparse and dense matrix operations (add, multiply, scale, et cetera)
modify Enable Cholesky-modification routines like update, downdate, row-add, and row-delete
partition Enable graph partitioning and graph-partition-based orderings through sci-libs/metis (using a bundled fork in 4.0.0+) or sci-libs/parmetis
supernodal supernodal cholesky factorisation

clblas

client Build a command line clBLAS client program.
ktest A command line tool for testing single clBLAS kernel.
performance Copy performance scripts that can measure and graph performance.

clblast

client Enable compilation of the clients to test and compare performance with reference libraries
cuda Build with support for cuda instead of opencl (beta!)
opencl Build with support for opencl

coinor-clp

glpk Enable GNU Linear Programming Kit sci-mathematics/glpk support
metis Enable partitioning with sci-libs/metis
mumps Enable sci-libs/mumps support
sparse Enable support for sparse matrix with sci-libs/cholmod

coinor-cppad

adolc Add support for ADOL-C (sci-libs/adolc)
eigen Add support for Eigen (dev-cpp/eigen)
ipopt Add support for IPOPT (sci-libs/ipopt)

coinor-symphony

glpk Enable GNU Linear Programming Kit sci-mathematics/glpk support

coinor-utils

glpk Enable GNU Linear Programming Kit sci-mathematics/glpk support

dealii

adolc Adds support for ADOL-C (sci-libs/adolc)
arborx Adds support for ARBORX (sci-libs/arborx)
arpack Adds support for ARPACK (sci-libs/arpack)
assimp Add support for assimp (media-libs/assimp)
cgal Adds support for CGAL (sci-mathematics/cgal)
cuda Add support for cuda (dev-util/nvidia-cuda-toolkit)
ginkgo Add support for ginkgo (sci-libs/ginkgo)
gmsh Add support for gmsh (sci-libs/gmsh)
metis Add support for metis (sci-libs/metis)
muparser Add support for muparser (dev-cpp/muParser)
opencascade Add support for opencascade (sci-libs/opencascade)
p4est Add support for p4est (sci-libs/p4est)
petsc Add support for petsc (sci-mathematics/petsc)
scalapack Add support for ScaLAPACK (sci-libs/scalapack)
slepc Add support for slepc (sci-mathematics/slepc)
sparse Add support for suitesparse (sci-libs/suitesparse)
sundials Add support for sundials (sci-libs/sundials)
symengine Add support for symengine (sci-libs/symengine)
trilinos Add support for trilinos (sci-libs/trilinos)

dlib

cblas Build with CBLAS virtual/cblas
cuda Enable support for CUDA for Deep Neural Networks (cuDNN) on GPU (experimental)
mkl Enable support for Intel FFT sci-libs/mkl
python Enable support for Python API bindings

dmlc-core

s3 Support for the Amazon Simple Storage Service

eccodes

defs Install full set of definition files.
extra-test Install full set of test data (large).
memfs Enable memory based access to definition/sample files (conflicts with tests).

fcl

octomap OctoMap library support
profiling Enable profiling

fftw

zbus Adds support for ZBus cycle-counter of mips

flann

cuda Enable support for nVidia CUDA
octave Add bindings for sci-mathematics/octave

fplll

qd Use sci-libs/qd for quad-double datatype

gdal

armadillo Use sci-libs/armadillo for faster TPS transform computation
fits Enable support for NASA's sci-libs/cfitsio library
geos Add support for geometry engine (sci-libs/geos)
gml Enable support for dev-libs/xerces-c C++ API
ogdi Enable support for the open geographic datastore interface (sci-libs/ogdi)
opencl Enable OpenCL support
spatialite Enable Spatial DBMS over sqlite dev-db/spatialite
xls Add the dev-libs/freexl library for xls import support

ginkgo

cuda Add support for cuda assimp (dev-util/nvidia-cuda-toolkit)
hwloc Add support for hwloc (sys-apps/hwloc)

gloo

cuda Enable CUDA support
libuv Enable libuv support
redis Enable Redis backend for storage via dev-libs/hiredis

gmsh

alglib Enable alglib support for mesh optimizers
cgns Enables cgns output support
eigen Build matrix manipulation with dev-cpp/eigen
gmm A simple alternative to petsc based on sci-mathematics/gmm
med Enables med support
metis Enables metis support
mumps Enables mumps solver support
netgen Enable 3D Frontal triangulation using netgen lib
opencascade Enable OpenCASCADE support
petsc Enable sci-mathematics/petsc support
shared Install shared library and headers
slepc Enable sci-mathematics/slepc support
voro Enable support to sci-libs/voro++ meshing

gsl

cblas-external Link gsl with external cblas provided by (virtual/cblas) instead of shipped internal version
deprecated Enable deprecated functions

hdf5

hl Enable high level API (https://support.hdfgroup.org/HDF5/doc/HL/index.html)
unsupported Enable unsupported combinations of configuration options

hipCUB

benchmark Build and install benchmark binaries.

hypre

int64 Build the 64 bits integer library

indilib

rtlsdr Enable support for devices supported by net-wireless/rtl-sdr
websocket Enable support for WebSocket protocol

ipopt

hsl hsl
mumps Enable sci-libs/mumps support

kissfft

alloca Use alloca(3) instead of malloc(3) for memory management
tools Build command line tools

lapack

deprecated Also build deprecated functions
eselect-ldso Enable runtime library switching by eselect and ld.so.
lapacke Build LAPACKE

lemon

coin Enable the sci-libs/coinor-clp and sci-libs/coinor-cbc graph algorithms
glpk Enable GNU Linear Programming Kit sci-mathematics/glpk support

libccd

double-precision More precise calculations at the expense of speed

libgeodecomp

cuda Enables plugins for NVIDIA GPUs
hpx Enables HPX backend
opencl Enables OpenCL backend
opencv Enables OpenCV related code
silo Enables SILO related code

libghemical

mopac7 Use sci-chemistry/mopac7 for semi-empirical calculations
mpqc Use sci-chemistry/mpqc for quantum-mechanical calculations

liborigin

tools Install opj2dat command line util

libqalculate

hardened Disable unsafe functions like 'command' and variables like 'uptime'.

libsc

romio Build with support for the ROMIO MPI-IO component

libsigrok

ftdi Enable drivers that need dev-embedded/libftdi
hidapi Enable drivers that need dev-libs/hidapi
nettle Enable drivers that need dev-libs/nettle
parport Enable drivers that are parallel (IEEE1284) based
serial Enable drivers that are serial (RS232) based

libsvm

tools Install python based tool scripts for data selection and visualization with sci-visualization/gnuplot

linbox

opencl Enable the use of OpenCL in LinBox

linux-gpib

firmware Install firmware

lis

quad Enable quadruple precision operations
saamg Build the Smoothed Aggregation Algebraic MultiGrid preconditioner

mathgl

hdf Add support for the Hierarchical Data Format v.4 sci-libs/hdf
octave Add bindings for sci-mathematics/octave

matio

sparse Extend formats for sparse matrix (not matlab)

metis

double-precision Use double- rather than single-precision floating-point representation
int64 Use 64- rather than 32-bit integer representation (needed for > 2^31 vertices)

mpir

cpudetection Enables runtime cpudetection (useful for bindist, compatibility on other CPUs)

mumps

metis Enable matrix ordering with METIS (sci-libs/metis, sci-libs/parmetis)
scotch Enable matrix ordering with sci-libs/scotch

netcdf

dap Support for remote data access with the built-in OPeNDAP client
hdf Add support for the Hierarchical Data Format v.4 sci-libs/hdf

nlopt

octave Add plugin for sci-mathematics/octave

o2scl

armadillo Build matrix manipulation with sci-libs/armadillo
eigen Build matrix manipulation with dev-cpp/eigen

octomap

dynamicEDT3D Build and install dynamicEDT3D library: A library for incrementally updatable Euclidean distance transforms in 3D.

openblas

dynamic Build dynamic architecture detection at run time (for multi targets)
eselect-ldso Enable BLAS/LAPACK runtime switching
index-64bit Compile a separate INTERFACE64 OpenBLAS
pthread Build with pthread threading model
relapack Build the ReLAPACK extension to OpenBLAS

opencascade

eigen Enable support for eigenvalues through the header-only dev-cpp/eigen package.
freeimage Enable support for image i/o via media-libs/freeimage
gles2 Use OpenGL ES 2.0
json Enable JSON support through dev-libs/rapidjson
optimize Don't clear allocated memory. Use optimized memory manager unless tbb USE flag is set.
tbb Enable multithreading with the Intel Threads Building Block dev-cpp/tbb
vtk Enable Visualization Toolkit support via sci-libs/vtk

orocos_kdl

models Build models for some well known robots.

p4est

romio Build with support for the ROMIO MPI-IO component
vtk-binary Enable binary vtk output. If disabled vtk files will be written in ASCII text format.

pastix

cuda Enable GPU support using CUDA kernels
fortran Install the Fortran interface
int64 Use 64- rather than 32-bit integer representation
metis Enable matrix ordering with sci-libs/metis
scotch Enable matrix ordering with sci-libs/scotch
starpu Enable support for ther dev-libs/starpu runtime

pcl

cuda Adds support for NVIDIA CUDA.
openni Adds support for Kinect-like 3D sensors devices with dev-libs/OpenNI.
openni2 Adds support for Kinect-like 3D sensors devices with dev-libs/OpenNI2 (should be preferred over openni).
pcap Adds pcap file capabilities in some drivers.
qhull Adds convex-hull operation support via media-libs/qhull.
tutorials Builds and installs tutorials.
vtk Adds support for VTK-Visualizations.

plplot

dynamic Build with dynamic drivers
octave Add bindings for sci-mathematics/octave
qhull Add bindings for media-libs/qhull
shapefile Enable support for ESRI shapefiles

rocBLAS

benchmark Build and install rocblas-bench.
test Perform rocblas-test to compare the result between rocBLAS and system BLAS.

rocFFT

benchmark Build and install [dyna-]rocfft-rider.
perfscripts Install rocfft-perf performance visualization suite.

rocPRIM

benchmark Build and install benchmark programs.

rocRAND

benchmark Build and install benchmark programs.

rocSOLVER

benchmark Build and install rocsolver-bench.
test Perform rocsolver-test to compare the result between rocSOLVER and system LAPACK.

rocSPARSE

benchmark Build and install rocblas-bench.

rocThrust

benchmark Build and install benchmark binary.

rtabmap

openni2 Adds support for Kinect-like 3D sensors devices with dev-libs/OpenNI2.

scotch

int64 Build the 64 bits integer library (needed for > 2^31 vertices)
tools Provides the graph, mesh, architecture, mapping/ordering, output handling programs (see Scotch User's Guide).

silo

browser Enable browser support
silex Build silex data browser

spqr

partition Use the partition module of sci-libs/cholmod for partitioning
tbb Enable multithreading with the Intel Threads Building Block dev-cpp/tbb

spr

root Add sci-physics/root graphics and i/o support

suitesparse

cuda Enable nvidia cuda toolkit for speeding up computations
partition Enable graph partitioning and graph-partition-based orderings through sci-libs/metis or sci-libs/parmetis
tbb Enable multithreading with the Intel Threads Building Block dev-cpp/tbb

sundials

hypre Build with sci-libs/hypre conditioners
int64 Use index size of 64 rather than 32 bits
sparse Enable support for sci-libs/klu sparse solver
superlumt Build with sci-libs/superlu_mt

superlu_mt

int64 Build the 64 bits integer library

symengine

arb Add support for arb (sci-mathematics/arb)
benchmarks Build benchmarks
boost Add support for boost integers(dev-libs/boost)
ecm Add support for ECM integer factorization library (sci-mathematics/gmp-ecm)
flint Add support for (sci-mathematics/flint)
llvm Build with LLVM
mpc Add support for multiprecision complex arithmetic(dev-libs/mpc)
mpfr Add support for multiprecision floating point rouding(dev-libs/mpfr)

tensorflow

cuda Enable support for nVidia CUDA
xla XLA (Accelerated Linear Algebra) Optimizing Compiler for TensorFlow

tensorpipe

cuda Add support for CUDA processing

trilinos

adolc Add support for adolc (sci-libs/adolc)
all-packages Enable all supported Trilinos packages (per default only a subset is built)
arprec Add support for arprec (sci-libs/arprec)
clp Add support for clp (sci-libs/coinor-clp)
cuda Add support for cuda (dev-util/nvidia-cuda-toolkit)
eigen Add support for eigen (dev-cpp/eigen)
glpk Add support for glpk (sci-mathematics/glpk)
gtest Add support for gtest (dev-cpp/gtest)
hdf5 Add support for hdf5 (sci-libs/hdf5)
hwloc Add support for hwloc (sys-apps/hwloc)
hypre Add support for hypre (sci-libs/hypre)
matio Add support for matio (sci-libs/matio)
metis Add support for metis (sci-libs/metis or sci-libs/parmetis)
mkl Add support for mkl (sci-libs/mkl)
mumps Add support for mumps (sci-libs/mumps)
netcdf Add support for netcdf (sci-libs/netcdf)
petsc Add support for petsc (sci-mathematics/petsc)
qd Add support for qd (sci-libs/qd)
scalapack Add support for scalapack (sci-libs/scalapack)
scotch Add support for scotch (sci-libs/scotch)
sparse Add support for sparse matrix solvers (sci-libs/umfpack)
superlu Add support for superlu (sci-libs/superlu)
taucs Add support for taucs (sci-libs/taucs)
tbb Add support for threading building blocks library (dev-cpp/tbb)
tvmet Add support for tvmet (dev-libs/tvmet)
yaml Add support for yaml (dev-cpp/yaml-cpp)

umfpack

cholmod Use sci-libs/cholmod for matrix ordering

vtk

all-modules Build all modules
boost Add support for boost
cuda Add support for CUDA
freetype Build support for font rendering
gdal Support for gdal formated data
imaging Building Imaging modules
las Build support for LiDAR files
logging Build the logging module
openvdb Build support to handle VDB data files
pdal Build support to handle point cloud data files
qt6 Use Qt6 packages instead of Qt5
rendering Building Redering modules
sdl Enable SDL2 support for rendering modules
tbb Use dev-cpp/tbb to handle smp support
views Building Views modules
vtkm Build the vtkm accelerations modules
web Install web component

sci-mathematics

bertini

optimization Accept upstream's choices for -O option.

boolector

cryptominisat Enable support for sci-mathematics/cryptominisat
minisat Enable support for sci-mathematics/minisat
picosat Enable support for sci-mathematics/picosat

cadabra

jupyter Build the Cadabra Jupyter kernel

cvc4

cln Use sci-libs/cln
proofs Support for proof generation
statistics Include statistics

eclib

boost Add parallel capabilities using dev-libs/boost.
flint Enable the use of sci-mathematics/flint for certain operations.
minimal Build only the "mwrank" program.

eprover

ho enable support for higher-order logic

flint

ntl Build NTL interface

form

devref Build and install developers reference
doxygen Build and install API documentation

fricas

clisp Add support for GNU CLISP (dev-lisp/clisp)
clozurecl Add support for Clozure Common Lisp (dev-lisp/clozurecl)
cmucl Add support for CMU Common Lisp (dev-lisp/cmucl)
ecl Add support for Embeddable Common Lisp (dev-lisp/ecl)
gcl Add support for GNU Common Lisp (dev-lisp/gcl)
sbcl Add support for Steel Bank Common Lisp (dev-lisp/sbcl)

geomview

motionaveraging Enable experimental motion averaging technique

giac

ecm Enable the use of sci-mathematics/gmp-ecm
gc Enable garbage collection support via dev-libs/boehm-gc
glpk Enable the use of sci-mathematics/glpk

gmp-ecm

custom-tune Improve performance of some operations by selecting machine-specific defaults

gretl

R Enable support for dev-lang/R
extras Build and install add-ons bundled with gretl

gsl-shell

fox Build a x11-libs/fox GUI

lcalc

double Use double precision (the upstream default)
double-double Use sci-libs/qdfor double-double precision
pari Use sci-mathematics/pari for elliptic curve L-functions
quad-double Use sci-libs/qdfor quad-double precision

mathematica

R Enable dev-lang/R backend support
bundle Install from Wolfram's bundle file or from Mathematica only
cuda Install with cuda support
ffmpeg Enable media-video/ffmpeg backend support

maxima

clisp Compile maxima with GNU CLISP (dev-lisp/clisp)
clozurecl Compile maxima with 32-bit Clozure Common Lisp (dev-lisp/clozurecl)
clozurecl64 Compile maxima with 64-bit Clozure Common Lisp (dev-lisp/clozurecl)
cmucl Compile maxima with CMU Common Lisp (dev-lisp/cmucl)
ecl Compile maxima with Embeddable Common Lisp (dev-lisp/ecl)
gcl Compile maxima with GNU Common Lisp (dev-lisp/gcl)
sbcl Compile maxima with Steel Bank Common Lisp (dev-lisp/sbcl)
vtk Support plotting with sci-libs/vtk

msieve

ecm Enable support for the GMP-ECM library

normaliz

extras Install Macaulay2 and sci-mathematics/singularpackages as shipped by upstream
nauty Use sci-mathematics/nauty to compute automorphism groups.

octave

fltk Use x11-libs/fltk as the backend for the OpenGL renderer in the absence of the Qt GUI
glpk Add support for sci-mathematics/glpk for linear programming
gnuplot Use sci-visualization/gnuplot to render plots if OpenGL is unavailable
imagemagick Use media-gfx/graphicsmagick to read and write images
json Allow using jsonencode and jsondecode commands via dev-libs/rapidjson
qhull Add support for media-libs/qhull, to allow `delaunay', `convhull', and related functions
qrupdate Add support for sci-libs/qrupdatefor QR and Cholesky update functions
sparse Add enhanced support for sparse matrix algebra with SuiteSparse
sundials Enable the ode15i and ode15s ODE solvers using sci-libs/sundials

pari

data Add additional data (elldata, galdata, seadata, nftables)

petsc

afterimage Use Afterstep image library (media-libs/libafterimage)
boost Use boost (dev-libs/boost)
complex-scalars Make scalars complex
hypre Use HYPRE (sci-mathematics/hypre) and for preconditioning
int64 Use 64 bit indexes
metis Add support for metis (sci-libs/parmetis)
mumps Add support for mumps (sci-libs/mumps)
scotch Add support for scotch (sci-libs/scotch)
sparse Use suitesparse (sci-libs/suitesparse) including cholmod (sci-libs/cholmod) for sparse factorization
superlu Use superlu (sci-libs/superlu) for preconditioning

polymake

bliss Enable sci-libs/bliss interface for graph and face lattice isomorphism computations.
cdd Enable sci-libs/cddlib interface for convex hull computations (Should be kept enabled).
flint Build with "strongly recommended" support for sci-mathematics/flint.
libpolymake Build the polymake library to build applications using the C++ interface.
lrs Enable sci-libs/lrslib interface for convex hull computations.
nauty Build the extension for graph automorphism computations using sci-mathematics/nauty.
normaliz Build the bundled extension for lattice computations using sci-mathematics/normaliz.
ppl Enable dev-libs/ppl interface for convex hull computations.
singular Enable the interface to sci-mathematics/singular for ideal related computations.

primecount

executable Build the primecount CLI executable

primesieve

executable Build the primesieve CLI executable

singular

polymake Enable the interface to TOPCOM

slepc

arpack Adds support for ARPACK (sci-libs/arpack)
complex-scalars Make scalars complex

stp

cryptominisat Enable sci-mathematics/cryptominisat support
python Enable building the Python interface

unuran

prng Use sci-mathematics/prng library
rngstreams Use sci-mathematics/rngstreams library

vampire

z3 Enable support for sci-mathematics/z3

why3

coq Add sci-mathematics/coq support
gtk Build the IDE x11-libs/gtk+
re Use Re (dev-ml/re) instead of Str for regular expressions
sexp Add support for outputting S-expressions with dev-ml/ppx_sexp_conv
stackify Enable structure reconstruction algorithm for MLCFG
zarith Use Zarith (dev-ml/zarith) instead of Nums (dev-ml/num) for computations
zip Enable compression of session files

why3-for-spark

coq Add sci-mathematics/coq support
html Build HTML documentation
hypothesis-selection Enable hypothesis selection
sexp Add support for outputting S-expressions with dev-ml/ppx_sexp_conv
zarith Use Zarith (dev-ml/zarith) instead of Nums (dev-ml/num) for computations
zip Enable compression of session files

wxmaxima

webkit Use net-libs/webkit-gtk to show help (for maxima and wxmaxima) inside wxmaxima

yacas

jupyter Add support for jupyter notebook

yices2

mcsat Enable support for MCSAT

z3

isabelle Add integration support for the Isabelle/HOL theorem prover.

sci-misc

boinc

cuda Use nvidia cuda toolkit for speeding up computations. NOTE: works only for subset of nvidia graphic cards so make sure your card is supported before opening a bug about it.
opencl Use OpenCL to enable computations using your GPU.

h5utils

hdf Build hdf to hdf5 (and vice-versa) converter
octave Build Octave plugins

nco

dap Support for remote data access with the NETCDF DAP client
ncap2 Build next generation netcdf arithmetic processor (needs dev-java/antlr)
udunits Add sci-libs/udunits files support

sci-physics

bullet

double-precision Build libraries in double precision
extras Build the extras
tbb Enable multithreading with the Intel Threads Building Block dev-cpp/tbb

espresso

cuda Enable cuda support
examples Installs the examples

fastjet

cgal Use sci-mathematics/cgal instead of bundled algorithms
plugins Build all standard and C++ plugins

geant

c++17 Build using the C++17 standard
c++20 Build using the C++20 standard
data Add a lot of standard physics data files for geant4
freetype Add support for media-libs/freetype
gdml Enable geometry markup language for xml
geant3 Add compatibility for geant321 to geant4
inventor Add support for Open Inventor SGI toolkit via Coin3D
raytracerx Enable raytracing for physics events
tbb Enable support for dev-cpp/tbb
trajectories Enable display of particle trajectories
vtk Use sci-libs/vtk for visualization (experimental)

geant4_vmc

g4root Build G4Root (interface for GEANT4 simulation with a ROOT geometry)
geant3 Build with Geant4 G3toG4 library
vgm Enable the Virtual Geometry Model (sci-physics/vgm)

hepmc

cm Build with cm instead of default mm for length units
gev Build with GeV instead of default MeV for momentum units
root Build with ROOTIO enabled

lammps

cuda Enable cuda gpu computing support
hip Enable hip gpu computing support
lammps-memalign Enables the use of the posix_memalign() call instead of malloc() when large chunks or memory are allocated by LAMMPS. Aliengnment is on 16 byte boundaries.
opencl Enable opencl gpu computing support

pythia

fastjet Build jets using the sci-physics/fastjet package
hepmc Adds support for High Energy Physics Monte Carlo Generators sci-physics/hepmc
hepmc2 Adds support for High Energy Physics Monte Carlo Generators 2 sci-physics/hepmc
hepmc3 Adds support for High Energy Physics Monte Carlo Generators 3 sci-physics/hepmc
lhapdf Support the use of external PDF sets via sci-physics/lhapdf
root Use sci-physics/root trees and histograms (in examples only)

root

R Enable support for dev-lang/R
asimage Enable support for media-libs/libafterimage
c++14 Build using the C++14 standard
c++17 Build using the C++17 standard
cuda Enable support for nVidia CUDA
cudnn Enable support for nVidia cuDNN library
davix Enable support for DAVIX Data Management Client (https://cern.ch/davix)
fits Enable support for images and data from FITS files with sci-libs/cfitsio
fortran Compile included Fortran programs
gdml Enable GDML writer and reader
http Enable http server support including but not limited to fastcgi support
jupyter Install dependencies to enable ROOT's C++ kernel in Jupyter notebooks
libcxx Build ROOT against sys-libs/libcxx
minuit Build ROOT's internal versions of minuit (fortran) and minuit2 (C++)
pythia6 Build the interface for sci-physics/pythia version 6.x
pythia8 Build the interface for sci-physics/pythia version 8.x
roofit Build RooFit function fitting package
root7 Build experimental features to be released with ROOT 7
shadow Enable shadow authentication in rootd and proofd
tbb Enable implicit multi-threading (IMT) with dev-cpp/tbb
tmva Built TMVA (ROOT's multi-variate analysis toolkit for machine learning)
unuran Enable support for sci-mathematics/unuran
uring Enable support for sys-libs/liburing in RNTuple
vc Enable support for dev-libs/vc with VecCore
xrootd Build the interface for net-libs/xrootd

thepeg

fastjet Adds support for sci-physics/fastjet
hepmc Adds support for High Energy Physics Monte Carlo Generators sci-physics/hepmc
lhapdf Adds support for sci-physics/lhapdf

vgm

geant4 Enable interaction with Geant4(sci-physics/geant:4)
root Enable interaction with ROOT (sci-physics/root)

vmc

c++14 Build using the C++14 standard
c++17 Build using the C++17 standard

yoda

root Adds support for sci-physics/root

sci-visualization

fityk

nlopt Enable optimization with sci-libs/nlopt

gnuplot

bitmap Enable dot-matrix printers and pbm terminal
gd Add support for media-libs/gd. Needed for GIF, JPEG, and PNG image output.
libcerf Enable special functions from sci-libs/libcerf
regis Enable ReGIS terminal

gr

agg Enable the libagg anti-grain rendering engine

gwyddion

fits Enable FITS image import via sci-libs/cfitsio
jansson Enable JSON data manipulation via dev-libs/jansson
sourceview Enable support for x11-libs/gtksourceview
unique Enable remote control backend via dev-libs/libunique

labplot

cantor Enable support for different open-source computer algebra systems via kde-apps/cantor
excel Enable support for importing/exporting Microsoft Excel files (.xlsx) via dev-libs/qxlsx
fits Enable support for NASA's sci-libs/cfitsio library
libcerf Enable special functions from sci-libs/libcerf
markdown Enable Markdown support via app-text/discount
matio Enable support for matio (sci-libs/matio)
origin Enable support for reading OriginLab OPJ project files through sci-libs/liborigin
root Enable support for CERN's ROOT file type
serial Enable support for RS232 serial ports using dev-qt/qtserialport

paraview

boost Enable the usage of dev-libs/boost
cg Add support for nvidia's cg shaders
nvcontrol Add NVCONTROL support for OpenGL options
offscreen Offscreen rendering through OSMesa
plugins Build and install additional plugins
webengine Add support for dev-qt/qtwebengine

scidavis

origin Add support for reading OriginLab OPJ project files through sci-libs/liborigin.
python Build support for python scripting.

sec-policy

selinux-base

ubac Enable User Based Access Control (UBAC) in the SELinux policy
unconfined Enable support for the unconfined SELinux module
unknown-perms Default allow unknown classes in kernels newer than the policy (SELinux policy capability).

selinux-base-policy

unconfined Enable support for the unconfined SELinux policy module

sys-apps

accountsservice

elogind Use sys-auth/elogind for session tracking
systemd Use sys-apps/systemd for session tracking

busybox

make-symlinks Create all the appropriate symlinks in /bin and /sbin.
math Enable math support in gawk (requires libm)
mdev Create the appropriate symlink in /sbin and install mdev.conf and support files
sep-usr Support a separate /usr without needing an initramfs by booting with init=/ginit
static Make the system rescue shell (/bin/bb) static so you can recover even when glibc is broken
systemd Support systemd

coreutils

caps Add Linux capabilities support in output of file utilities (ls, dir, ...) via sys-libs/libcap
hostname Build the hostname program
kill Build the kill program
multicall Build all tools into a single `coreutils` program akin to busybox to save space
openssl Use openssl libcrypto hash routines for hash functions
split-usr Enable this if /bin and /usr/bin are separate directories

cpu-x

cpu Use the dev-libs/libcpuid library for CPU info
force-libstatgrab Use sys-libs/libstatgrab to instead of sys-process/procps
gpu Use the media-libs/glfw library for GPU info
opencl Use the virtual/opencl library
pci Use the sys-apps/pciutils library for PCI info

dbus

elogind Use sys-auth/elogind for session tracking.
systemd Build with sys-apps/systemd at_console support

dbus-broker

launcher dbus-daemon compatibility launcher

debianutils

installkernel Install /sbin/installkernel script (for Linux). installkernel is required whenever a kernel will be installed via make install

dtc

yaml support .yaml-encoded device trees

duc

X Use X11 for the GUI instead of OpenGL. This is the recommended option
cairo Build support for exporting to PNG and PDF with x11-libs/cairo
leveldb Use dev-libs/leveldb as the backend
ncurses Build support for the ncurses client
sqlite Use dev-db/sqlite:3 as the backend
tokyocabinet Use dev-db/tokyocabinet as the backend

earlyoom

docs Generate man page

elfix

ptpax Enable PT_PAX_FLAGS support.
xtpax Enable XATTR_PAX_FLAGS support.

etckeeper

cron Install cron script

ethtool

netlink Enable netlink interface via net-libs/libmnl

firejail

X Enable X11 sandboxing
apparmor Enable support for custom AppArmor profiles
chroot Enable chrooting to custom directory
contrib Install contrib scripts
dbusproxy Enable DBus proxying to filter access in supporting profiles
file-transfer Enable file transfers between sandboxes and the host system
globalcfg Enable global config file
network Enable networking features
private-home Enable private home feature
userns Enable attaching a new user namespace to a sandbox (--noroot option)

flashrom

atahpt Highpoint (HPT) ATA/RAID controller support
atapromise Support for Promise PDC2026x (FastTrak/Ultra)
atavia Support for VIA VT6421A SATA controllers
buspirate-spi Enable Bus Pirate SPI programmer
ch341a-spi Enable WCH CH341A SPI programmer
dediprog Dediprog SF100 support
developerbox-spi Enable Devloperbox SPI recovery support
digilent-spi Enable support for Digilent iCEblink40 development board
dirtyjtag-spi Support for DirtyJTAG (a USB-JTAG firmware for STM32 MCUs)
drkaiser Enable Dr. Kaiser programmer
dummy Enable dummy tracing
ft2232-spi Enable ftdi programmer, flashing through FTDI/SPI USB interface
gfxnvidia Enable NVIDIA programmer
internal Enable internal/onboard support
internal-dmi Enable internal DMI decoding rather than use sys-apps/dmidecode
it8212 Support for ITE IT8212F ATA/RAID controllers
jlink-spi Support for SEGGER J-Link and compatible devices
linux-mtd Enable support for Linux mtd SPI flash devices
linux-spi Enable support for Linux userspace spidev interface
mediatek-i2c-spi Support for Mediatek LCD controllers
mstarddc-spi Support for SPI flash ROMs accessible through DDC in MSTAR-equipped displays
nic3com Enable 3Com NIC programmer
nicintel Support for Intel NICs
nicintel-eeprom Support for EEPROMs on Intel Gigabit network cards
nicintel-spi Support for SPI on Intel NICs
nicnatsemi Support for National Semiconductor NICs
nicrealtek Support for Realtek NICs
ogp-spi Enable support for OGP (Open Graphics Project) SPI flashing
parade-lspcon Enable support for Parade lspcon USB-C to HDMI protocol translator
pickit2-spi Support for SPI flash ROMs accessible via Microchip PICkit2
pony-spi Enable support for SI-Prog like hardware by Lancos
raiden-debug-spi Support for Chrome EC based debug tools - SuzyQable, Servo V4, C2D2 & uServo
rayer-spi RayeR SPIPGM hardware support
realtek-mst-i2c-spi Enable support for Realtek RTD2142 MST
satamv Enable programmer for Marvell SATA controllers
satasii Enable programmer for SiI SATA controllers
serprog Enable Serial Flasher programmer
stlinkv3-spi Enable SPI programmer using STLINK-V3
tools Install ich_descriptor_tool, a tool for reading descriptor-mode SPI-flash images for Intel chipsets
usbblaster-spi Enable support for Altera USB-Blaster dongles

fwupd

amdgpu Build and install AMD dGPU (Navi3x and above) plugin
amt Build and install Intel AMT plugin
archive Use app-arch/libarchive for archives support
cbor Enable CBOR support for coSWID and uSWID via dev-libs/libcbor
dell Enable Dell-specific support
fastboot Build and install fastboot plugin
flashrom Enable flashrom plugin via sys-apps/flashrom
gusb Enable dev-libs/libgusb support
logitech Build and install Logitech bulk controller plugin
modemmanager Build and install Modem Manager plugin
nvme Build and install NVMe plugin
spi Install Intel-SPI plugin
synaptics Install synaptics plugin
test-full Enable tests known not to play nicely with the sandbox
tpm Install Trusted Platform Module plugin
uefi Enable UEFI support

gawk

mpfr Use dev-libs/mpfr for high precision arithmetic (-M / --bignum)
pma Experimental Persistent Memory Allocator (PMA) support which allows persistence of variables, arrays, and user-defined functions across runs.

gnome-disk-utility

fat Include FAT16/FAT32 support (sys-fs/dosfstools)

grep

egrep-fgrep Install deprecated 'egrep' and 'fgrep' wrappers for 'grep -E' and 'grep -F' respectively. GNU grep 3.8 onwards warns about their usage by default, but the versions installed by this flag do not. No deprecation warnings are emitted when this flag is enabled.

groff

uchardet Enable automatic encoding detection via app-i18n/uchardet

hwloc

X use the X Window System
cairo Enable the Cairo back-end of hwloc's lstopo command
cpuid Enable the cpuid-based architecture specific support (x86 component)
cuda Enable CUDA device discovery using libcudart
gl Enable GL display device discovery (NVCtrl)
numa Add support for numa memory allocation
nvml Enable the NVML device discovery
pci Enable PCI device discovery using libpci
plugins Build hwloc components as plugins so that the hwloc core library does not directly depend on their dependencies (for instance the libpci library)
xml use libxml2 for XML support, instead of a custom minimalistic support

ibm-powerpc-utils

rtas Add support for the Run Time Abstraction Services (RTAS)

iotools

make-symlinks Generate sub-command symlinks to iotools -- note that a lot are simple like "xor"

ipmicfg

uefi Install compatible UEFI file for boot.

ipmitool

openbmc Enable OpenBMC D-Bus interface
openipmi Use the system OpenIPMI implementation.

iproute2

berkdb build programs that use berkdb (just arpd)
bpf Use dev-libs/libbpf
elf support loading eBPF programs from ELFs (e.g. LLVM's eBPF backend)
iptables include support for iptables filtering
libbsd Use dev-libs/libbsd instead of internal funcs
minimal only install ip and tc programs, without eBPF support
nfs Support RPC lookups via net-libs/libtirpc in ss

irqbalance

numa Support balancing IRQs across NUMA nodes
thermal Enable support of thermal events via sys-power/thermald
tui Enable build of irqbalance terminal user interface

kexec-tools

booke Include support for Book-E memory management
lzma Enables support for LZMA compressed kernel images
xen Enable extended xen support

kmod

lzma Enable support for XZ compressed modules
pkcs7 Enable PKCS#7 signature parsing for modinfo.
tools Install module loading/unloading tools.
zlib Enable support for gzipped modules

kmscon

drm Enable Linux DRM for backend
fbdev Enable Linux FBDev for backend
gles2 Enable GLES2 for backend
pango Enable pango font rendering
pixman Enable pixman font rendering
systemd Enable multiseat support via systemd

linux-misc-apps

usbip Include USB/IP binaries to replace net-misc/usbip

lm-sensors

contrib Installs user contributed configuration files so you don't need to find settings on your own for your system if somebody else has already created such a configuration for sensors/mainboards you are using.
sensord Enable sensord - a daemon that can be used to periodically log sensor readings from hardware health-monitoring chips

man-db

manpager Enable manpager wrapper for colorizing output

memtest86

serial Compile with serial console support

memtest86+

bios32 Compile a BIOS-bootable 32bit memtest image
bios64 Compile a BIOS-bootable 64bit memtest image
boot Install to /boot in addition to /usr/share/memtest86+/
efi32 Compile a EFI32-bootable 32bit memtest image
efi64 Compile a UEFI-bootable 64bit memtest image
iso32 Compile a 32bit ISO image
iso64 Compile a 64bit ISO image

moreutils

perl Install scripts written in Perl

net-tools

arp build the arp and rarp tools (for manipulating the ARP cache)
hostname build the hostname and dnsdomainname tools
plipconfig build the plipconfig tool (for working with old PLIP hardware)
slattach build the slattach tool (for working with old serial ports)

nvme-cli

hugepages Use huge pages for memory allocations via sys-libs/libhugetlbfs
json Support JSON output via dev-libs/json-c

openrazer

client Build the OpenRazer daemon client
daemon Build the OpenRazer daemon service

openrc

bash enable the use of bash in service scripts (experimental)
netifrc enable Gentoo's network stack (net.* scripts)
newnet enable the new network stack (experimental)
s6 install s6-linux-init
sysv-utils Install sysvinit compatibility scripts for halt, init, poweroff, reboot and shutdown
sysvinit control the dependency on sysvinit (experimental)

pciutils

dns Enable support for querying the central database of PCI IDs using DNS
kmod Enable sys-apps/kmod support for the -k switch in lspci command
zlib Support compressed pci.ids database

pcmciautils

staticsocket Add support for static sockets

pcsc-lite

embedded limit RAM and CPU ressources by disabling features
libusb Use dev-libs/libusb detection to hotplug new smartcard readers. This flag should only be enabled if you're running a non-Linux kernel or you don't want to use udev.
policykit Uses sys-auth/polkit to restrict access to smartcard readers or smartcards to given users.
udev Use virtual/libudev rules to handle devices' permissions and hotplug support. Unless you know what you're doing do not disable this flag on Linux kernels. This is provided as an option for completeness.

pcsc-tools

network-cron Install a monthly cronjob to update the update-smartcard_list script

plocate

io-uring Enable efficient I/O via sys-libs/liburing.

policycoreutils

audit Enable support for sys-process/audit and use the audit_* functions (like audit_getuid instead of getuid())

portage

apidoc Build html API documentation with sphinx-apidoc.
gentoo-dev Enable features required for Gentoo ebuild development.
ipc Use inter-process communication between portage and running ebuilds.
native-extensions Compiles native "C" extensions (speedups, instead of using python backup code). Currently includes libc-locales. This should only be temporarily disabled for some bootstrapping operations. Cross-compilation is not supported.
rsync-verify Enable full-tree cryptographic verification of Gentoo repository rsync checkouts using app-portage/gemato.
xattr Preserve extended attributes (filesystem-stored metadata) when installing files. Usually only required for hardened systems.

ppc64-diag

rtas Add support for the Run Time Abstraction Services (RTAS)

proot

care Build dynamic CARE binary (more info - https://proot-me.github.io)

razercfg

gui Installs GUI configuration utility and status bar applet. Requires dev-python/PyQt5

rng-tools

jitterentropy Enable Jitter RNG entropy support
nistbeacon Enable NIST beacon entropy support
pkcs11 Enable PKCS11 entropy support
qrypt Enable qrypt beacon entropy support
rtlsdr Enable atmospheric-static entropy support with net-wireless/rtl-sdr

s390-tools

cryptsetup build the zkey-cryptsetup utility (requires USE=openssl)
fuse build cmsfs-fuse to read files stored on a z/VM CMS disk
ncurses build hyptop monitoring program
openssl build the zkey utility
pfm build the cpacfstats tool
zlib build the zgetdump and dump2tar utilities

s6

execline enable support for dev-lang/execline

s6-linux-init

sysv-utils Install sysvinit compatibility symlinks for telinit, halt, poweroff, reboot, and shutdown

sandbox

nnp Enable NO_NEW_PRIVS which blocks set*id programs from gaining privileges (e.g. sudo)

shadow

bcrypt build the bcrypt password encryption algorithm
su build the su program

smartmontools

caps Build against sys-libs/libcap-ng to allow smartd to drop its privileges.
daemon Install the monitoring daemon (smartd) and associated scripts.
update-drivedb Install a script to update the drivedb file.

smc-sum

module Install Supermicro's kernel module.

superdiag

iso Install an iso image, which can be used with sys-apps/smc-sum.
usb Install all files, which are needed for an installation on an usb thumb drive.

systemd

audit Enable support for sys-process/audit
boot Enable EFI boot manager and stub loader
cgroup-hybrid Default to hybrid (legacy) cgroup hierarchy instead of unified (modern).
cryptsetup Enable cryptsetup tools (includes unit generator for crypttab)
curl Enable support for uploading journals
dns-over-tls Enable DNS-over-TLS support
elfutils Enable coredump stacktraces in the journal
fido2 Enable FIDO2 support
gcrypt Enable use of dev-libs/libgcrypt for various features
gnuefi Enable EFI boot manager and stub loader (built using sys-boot/gnu-efi)
homed Enable portable home directories
http Enable embedded HTTP server in journald
importd Enable import daemon
iptables Use libiptc from net-firewall/iptables for NAT support in systemd-networkd; this is used only if the running kernel does not support nftables
kernel-install Enable kernel-install
kmod Enable kernel module loading via sys-apps/kmod
lz4 Enable lz4 compression for the journal
openssl Enable use of dev-libs/openssl for various features
pkcs11 Enable PKCS#11 support for cryptsetup and homed
pwquality Enable password quality checking in homed
qrcode Enable qrcode output support in journal
resolvconf Install resolvconf symlink for systemd-resolve
sysv-utils Install sysvinit compatibility symlinks and manpages for init, telinit, halt, poweroff, reboot, runlevel, and shutdown
tpm Enable TPM support
ukify Enable systemd-ukify
vanilla Disable Gentoo-specific behavior and compatibility quirks
xkb Depend on x11-libs/libxkbcommon to allow logind to control the X11 keymap

systemd-utils

boot Enable systemd-boot (UEFI boot manager)
kernel-install Enable kernel-install
kmod Enable kernel module loading via sys-apps/kmod
sysusers Enable systemd-sysusers
tmpfiles Enable systemd-tmpfiles
udev Enable systemd-udev (userspace device manager)
ukify Enable systemd-ukify

tcp-wrappers

netgroups Support matching NIS (host) netgroup names via the @netgroup syntax (if you don't know what this means, you most likely do not need it)

texinfo

standalone Build standalone version that survives all Portage bugs

usbguard

umockdev Enables support for dev-util/umockdev

usermode-utilities

fuse Build tools (currently umlmount) needing fuse

util-linux

audit Use sys-process/audit to emit audit messages about system changes
caps build setpriv helper (run programs with diff capabilities)
cramfs build mkfs/fsck helpers for cramfs filesystems
cryptsetup Use sys-fs/cryptsetup to have built-in dm-verity in libmount
fdformat build fdformat (floppy disk format)
hardlink build hardlink program
kill build the kill program
logger build the logger program
pam build runuser helper
rtas Add support for the Run Time Abstraction Services (RTAS)
su build the su program
suid Install some programs with suid bit set to provide additional functionality. mount/umount: non-root users may mount/umount devices wall/write: non-root users can notify other users su: non-root users may become root
tty-helpers install the mesg/wall/write tools for talking to local users

watchdog

nfs enable support for checking nfs mounts

xdg-desktop-portal

flatpak Enable sys-apps/flatpak integration
seccomp Use sys-apps/bubblewrap (which requires seccomp) to sandbox some functionality like icon handling

xinetd

rpc support RPC services

sys-auth

elogind

cgroup-hybrid Use hybrid cgroup hierarchy (OpenRC's default) instead of unified.

munge

gcrypt Use libgcrypt instead of openssl

nss-pam-ldapd

pynslcd Install the python implementation along with the standard implementation
utils Install the command-line utilities

oath-toolkit

pam Build PAM module for pluggable login authentication for OATH

pam_mktemp

prevent-removal If supported, set EXT2_APPEND_FL on /tmp/.private to prevent temporary directories from being removed

pam_mysql

openssl Use OpenSSL for md5 and sha1 support

pam_u2f

debug Enable debug messages using the pam logging macros.

pambase

debug Enable debug information logging on syslog(3) for all the modules supporting this in the system authentication and system login stacks.
elogind Use pam_elogind module to register user sessions with elogind.
homed Use pam_systemd_home module to manage home directories with the systemd-homed service
minimal Disables the standard PAM modules that provide extra information to users on login; this includes pam_lastlog, pam_motd, pam_mail and other similar modules. This might not be a good idea on a multi-user system but could reduce slightly the overhead on single-user non-networked systems.
mktemp Enable pam_mktemp module on system auth stack for session handling. This module creates a private temporary directory for the user, and sets TMP and TMPDIR accordingly.
nullok Enable the nullok option with the pam_unix module. This allows people to login with blank passwords.
pam_krb5 Enable pam_krb5 module on system auth stack, as an alternative to pam_unix. If Kerberos authentication succeed, only pam_unix will be ignore, and all the other modules will proceed as usual, including Gnome Keyring and other session modules. It requires sys-libs/pam as PAM implementation.
pam_ssh Enable pam_ssh module on system auth stack for authentication and session handling. This module will accept as password the passphrase of a private SSH key (one of ~/.ssh/id_rsa, ~/.ssh/id_dsa or ~/.ssh/identity), and will spawn an ssh-agent instance to cache the open key.
passwdqc Enable pam_passwdqc module on system auth stack for password quality validation. This module produces warnings, rejecting or providing example passwords when changing your system password. It is used by default by OpenWall GNU/*/Linux and by FreeBSD.
pwhistory Enable pam_pwhistory module on system auth stack to save the last passwords for each user in order to force password change history and keep the user from alternating between the same password too frequently.
pwquality Enable pam_pwquality module on system auth stack for passwd quality validation. It is used by default by Fedora GNU/*/Linux.
securetty Enable pam_securetty module in the login stack. Not generally relevant anymore as the login stack only refers to local logins and local terminals imply secure access in the first place.
sha512 Switch Linux-PAM's pam_unix module to use sha512 for passwords hashes rather than MD5. This option requires sys-libs/pam version 1.0.1 built against sys-libs/glibc version 2.7, if it's built against an earlier version, it will silently be ignored, and MD5 hashes will be used. All the passwords changed after this USE flag is enabled will be saved to the shadow file hashed using SHA512 function. The password previously saved will be left untouched. Please note that while SHA512-hashed passwords will still be recognised if the USE flag is removed, the shadow file will not be compatible with systems using an earlier glibc version.
systemd Use pam_systemd module to register user sessions in the systemd control group hierarchy.
yescrypt Switch Linux-PAM's pam_unix module to use yescrypt for passwords hashes rather than MD5

polkit

daemon Build polkitd in addition to libpolkit. Those using sys-apps/dbus-broker may wish to disable this flag.
duktape Use dev-lang/duktape instead of dev-lang/spidermonkey as JavaScript engine
systemd Use sys-apps/systemd for session tracking

seatd

builtin Enable embedded server in libseat
server Enable standalone seatd server, replacement to (e)logind

ssh-ldap-pubkey

schema Install a copy of the LPK schema, only needed on LDAP servers.

sssd

acl Build and use the cifsidmap plugin
locator Install sssd's Kerberos plugin
netlink Add support for netlink protocol via dev-libs/libnl
nfsv4 Add support for the nfsv4 idmapd plugin provided by net-fs/nfs-utils
pac Add Privileged Attribute Certificate Support for Kerberos
samba Add Privileged Attribute Certificate Support for Kerberos
subid Support subordinate uid and gid ranges in FreeIPA
sudo Build helper to let app-admin/sudo use sssd provided information
systemtap Enable SystemTAP/DTrace tracing

sys-block

f3

extra Build the additional f3probe, f3brew and f3fix utility (requires sys-block/parted and virtual/udev)

fio

aio Enable AIO ioengine
curl Enable HTTP engine for S3 and WebDav support support via net-misc/curl
glusterfs Enable GlusterFS gfapi support via sys-cluster/glusterfs
gnuplot Install tools for generating gnuplots
io-uring Enable efficient I/O via sys-libs/liburing.
nfs Enable NFS support
numa Enable numa support
rbd Enable Rados block device support via sys-cluster/ceph
rdma Enable infiniband support via sys-cluster/rdma-core
tcmalloc Link against dev-util/google-perftools by default which will speed up USE=rbd up to 20%
zbc Enable ZBC & ZAC disks via sys-block/libzbc.

gparted

wayland Enable interim workaround to allow running GParted under Wayland by granting permission to the X11 display using x11-apps/xhost

libfabric

cuda Enable for CUDA provider
efa Enable Amazon EC2 Elastic Fabric Adapter provider
rocr Enable Radeon Open Compute provider
usnic Enable Cisco VIC (virtualized NIC) hardware on Cisco UCS server provider
verbs Enable Linux Infiniband verbs provider

nbd

netlink Add support for netlink protocol via dev-libs/libnl

nbdkit

ext2 Enable the ext2 filter via sys-fs/e2fsprogs.
libguestfs Enable the app-emulation/libguestfs plugin.
libssh Enable the SSH plugin via net-libs/libssh.
libvirt Enable the app-emulation/libvirt plugin.
nbd Enable the nbd plugin via sys-libs/libnbd.
torrent Enable the torrent plugin via net-libs/libtorrent-rasterbar.
zlib-ng Use sys-libs/zlib-ng to handle zlib decompression.

ndctl

libtracefs Use dev-libs/libtracefs to build cxl-monitor binary

open-iscsi

rdma Support iSCSI over RDMA
tcp Support iSCSI over TCP

parted

debug Enable debugging as encouraged by upstream: [The default configuration] includes --enable-debug (by default), which contains many assertions. Obviously, these "waste" space, but in the past, they have caught potentially dangerous bugs before they would have done damage, so we think it's worth it. Also, it means we get more bug reports ;)
device-mapper Enable device-mapper support from sys-fs/lvm2 in parted

partimage

nologin Do not include login support when connecting partimaged

perccli

efi Install EFI variant as well

sas2ircu

efi Install EFI variant as well

sas3flash

efi Install EFI variant as well

sas3ircu

efi Install EFI variant as well

tgt

fcoe Add support for FCoE protocol
fcp Add support for new FC protocol
ibmvio Add support for IBM Virtual I/O
rbd Add support for ceph block devices

thin-provisioning-tools

io-uring Enable experimental support for io-uring.

sys-boot

grub

device-mapper Enable support for device-mapper from sys-fs/lvm2
efiemu Build and install the efiemu runtimes
fonts Build and install fonts for the gfxterm module
libzfs Enable support for sys-fs/zfs
mount Build and install the grub-mount utility
themes Build and install GRUB themes (starfield)
truetype Build and install grub-mkfont conversion utility

lilo

device-mapper Enable support for device-mapper from sys-fs/lvm2
minimal Do not install the dolilo helper script
pxeserial Avoid character echo on PXE serial console

plymouth

drm Provides abstraction to the DRM drivers (intel, nouveau and vmwgfx at this moment)
pango Adds support for printing text on splash screen and text prompts, e.g. for password
split-usr Enable this if /bin and /usr/bin are separate directories

refind

btrfs Builds the EFI binary btrfs filesystem driver
ext2 Builds the EFI binary ext2 filesystem driver
ext4 Builds the EFI binary ext4 filesystem driver
hfs Builds the EFI binary hfs filesystem driver
iso9660 Builds the EFI binary iso9660 filesystem driver
ntfs Builds the EFI binary ntfs filesystem driver
reiserfs Builds the EFI binary reiserfs filesystem driver

silo

tilo-only Install only the tilo netboot tool

syslinux

bios Enable BIOS support
efi Enable EFI support

vboot-utils

libzip Use dev-libs/libzip.

sys-cluster

ceph

babeltrace Add support for LTTng babeltrace
cephfs Build support for cephfs, a POSIX compatible filesystem built on top of ceph
diskprediction Enable local diskprediction module to predict disk failures
dpdk Enable DPDK messaging
fuse Build fuse client
grafana Install grafana dashboards
jaeger Enable jaegertracing and it's dependent libraries
kafka Rados Gateway's pubsub support for Kafka push endpoint
lttng Add support for LTTng
mgr Build the ceph-mgr daemon
numa Use sys-process/numactl for numa support in rocksdb
parquet Support for s3 select on parquet objects
pmdk Enable PMDK libraries
rabbitmq Use rabbitmq-c to build rgw amqp push endpoint
radosgw Add radosgw support
rbd-rwl Enable librbd persistent write back cache
rbd-ssd Enable librbd persistent write back cache for SSDs
rdma Enable RDMA support via sys-cluster/rdma-core
rgw-lua Rados Gateway's support for dynamically adding lua packagess
spdk Enable SPDK user-mode storage driver toolkit
system-boost Use system dev-libs/boost instead of the bundled one
uring Build with support for sys-libs/liburing
xfs Add xfs support
zbd Enable sys-block/libzbd bluestore backend
zfs Add zfs support

charliecloud

ch-image Build the internal builder ch-image (previously named ch-grow)

charm

ampi Build implementation of MPI on top of Charm++
charmdebug Enable the charm debugger
charmproduction Optimize performance of Charm++ runtime
charmtracing Enable tracing support in Charm++
cmkopt Enable CMK optimisation
mlogft Compile with Charm++ message logging fault tolerance support
numa Support memory affinity with NUMA
syncft Compile with Charm++ fault tolerance support
tcp Use TCP (instead of UPD) for socket communication

cluster-glue

ipmilan Install the ipmilan plugin (requires sys-libs/openipmi)
libnet Force use of net-libs/libnet

corosync

augeas Enable augeas support
watchdog Enable watchdog support

drbd-utils

pacemaker Enable Pacemaker integration
xen Enable Xen integration

galera

garbd Install Galera Arbitrator - a stateless daemon which acts as a lightweight group member

glusterfs

fuse Add FUSE mount helper
georeplication Enable support for georeplication (requires dev-lang/python)
ipv6 Use IPv6 by default, requires libtirpc
libtirpc Build against net-libs/libtirpc for RPC support
rsyslog Install configuration snippet for app-admin/rsyslog
uring Control whether or not glusterfs is compiled with uring support or not.

hpx

papi Use dev-libs/papi for NaCl
perftools Use dev-util/google-perftools for memory allocation
tbb Use dev-cpp/tbb for memory allocation

k3s

kubectl-symlink Install a kubectl symlink that points to k3s.
rootless Enables dependencies for running in rootless mode.

keepalived

bfd compile with support for Bidirectional Forwarding Detection (BFD).
json compile with signal to dump configuration and stats as JSON.
regex compile with support for regex in health checks

kronosnet

lzo2 Add support for lzo2 compression
nss Add support for tls via nss
openssl Add support for tls via openssl

legion

gasnet Enable GASNet lib support
hwloc Enable HWLoc lib support

lmod

auto-swap enable auto swapping of compiler
cache enable caching of modules
duplicate-paths allow duplicate entries in path

minikube

libvirt Build plugin for kvm

mpich

mpi-threads Enable MPI_THREAD_MULTIPLE
romio Build the ROMIO MPI-IO component

nomad

ui do not embed the ui in the binary

openmpi

cma Enable the CMA (Cross Memory Attach) MCA
cuda Add GPU direct support
libompitrace Enable support for contributed package libompitrace
peruse Enable PERUSE interface
romio Build the ROMIO MPI-IO component

pacemaker

smtp Enable SMTP support via net-libs/libesmtp

pmix

munge Enable authentication via munge
pmi Build PMI1 and PMI2 interface

rdma-core

lttng Enable support for the LTTng tracer
neigh Enable iwpmd support
python Enable pyverbs support

resource-agents

libnet Force use of net-libs/libnet
rgmanager Install resources for rgmanager

slurm

html Build html documentation
ipmi Build support for collecting some ipmi stats
json Add support for json-persing via json-c
multiple-slurmd Allow multiple slurmd to run
munge Enable authentication via munge
numa Add NUMA awareness
nvml Enable the NVML device discovery
ofed Add Infiniband support via ofed
rrdtool Enable RRD export plugin
slurmdbd Install SQL server for slurmdbd
slurmrestd Enable interface to Slurm via REST API
torque Enable perl scripts that emulates pbs (qstat, qsub etc.)
ucx Enable Unified Communication X library support
yaml Enable YAML support

spark-bin

scala211 Install Spark JARs pre-built with Scala 2.11.
scala212 Install Spark JARs pre-built with Scala 2.12.

torque

autorun Enable the AUTORUN_JOBS codebase
cgroups Enable pbs_mom to use linux cgroups to isolate jobs
cpusets Enable pbs_mom to utilize linux cpusets if available
munge Enable authentication via munge
nvidia Enable management of Nvidia GPUs
quickcommit Enable the QUICKCOMMIT codebase
server Enable compilation of pbs_server and pbs_sched

ucx

numa Add support for numa memory allocation

vzctl

ploop Add support for ploop devices via sys-cluster/ploop
vzmigrate Add support for container migration

sys-devel

autogen

libopts install the libopts tarball (a few packages want this for developing)

binutils

cet Enable Intel Control-flow Enforcement Technology.
debuginfod Enable debuginfod support via dev-libs/elfutils libdebuginfod
default-gold Set ld to point to ld.gold instead of ld.bfd
gold Build ld.gold linker
gprofng Enable the next-generation gprofng profiler
multitarget Adds support to binutils for cross compiling (does not work with gas)
pgo Build binutils with Profile Guided Optimization (PGO) and LTO
plugins Enable plugin support in tools

binutils-apple

classic Use nm, otool, etc. from this ebuild instead of llvm-based tools
lto Add support for Link-Time Optimization with LLVM

binutils-config

native-symlinks Install native symlinks like 'as' or 'ar' to /usr/bin. Otherwise keep only ${CTARGET}-as and friends.

binutils-hppa64

cet Enable Intel Control-flow Enforcement Technology.
default-gold Set ld to point to ld.gold instead of ld.bfd
gold Build ld.gold linker
gprofng Enable the next-generation gprofng profiler
multitarget Adds support to binutils for cross compiling (does not work with gas)
pgo Build binutils with Profile Guided Optimization (PGO) and LTO
plugins Enable plugin support in tools

clang

default-compiler-rt Use compiler-rt instead of libgcc as the default rtlib for clang
default-libcxx Use libc++ instead of libstdc++ as the default stdlib for clang
default-lld Use lld as the default linker for clang
extra Build extra tools (clangd, clang-tidy and a few more)
ieee-long-double Use accelerated 128-bit IEEE long double ABI (ppc64le only)
static-analyzer Install the Clang static analyzer

clang-common

default-compiler-rt Use compiler-rt + libunwind instead of libgcc as the default rtlib for clang
default-libcxx Use libc++ instead of libstdc++ as the default stdlib for clang
default-lld Use lld as the default linker for clang
stricter Default to stricter behavior known from newer clang versions, turning more warnings into errors

clang-runtime

compiler-rt Install sys-libs/compiler-rt for -rtlib=compiler-rt
libcxx Install sys-libs/libcxx for -stdlib=libc++
openmp Install sys-libs/libomp for -fopenmp support
sanitize Enable compiler-rt sanitizer (-fsanitize*) support
gcc-symlinks Install symlinks for 'gcc' and 'g++' for extra compatibility.
multilib-symlinks Install symlinks for all ABI CHOSTs. Note that this can result in gcc being overrode for native builds, as well as conflict with crossdev if used for the same targets.
native-symlinks Install generic tool symlinks like 'cc' and 'c++', as well as ${CTARGET}-*. These symlinks are installed into slotted LLVM bindir, so they should not take precedence over symlinks installed into /usr/bin by sys-devel/gcc-config but they can be helpful for GCC-free setups.

crosstool-ng

dtc Require sys-apps/dtc
lzip Require app-arch/lzip
meson Require dev-util/meson
ninja Require dev-util/ninja
rsync Require net-misc/rsync
wget Require net-misc/wget

distcc

gssapi Enable support for net-libs/libgssglue

gcc

ada Build the ADA language (GNAT) frontend
cet Enable support for Intel Control Flow Enforcement Technology (CET). Only effective on amd64/x86. Only provides benefits on newer CPUs. For Intel, the CPU must be at least as new as Tiger Lake. For AMD, it must be at least as new as Zen 3. This is harmless on older CPUs, but provides no benefit either. When combined with USE=hardened, GCC will set -fcf-protection by default when building software. The effect is minimal on systems which do not support it, other than a possible small increase in codesize for the NOPs. The generated code is therefore compatible with i686 at the earliest.
d Enable support for the D programming language
debug Enables GCC's 'checking' facility via --enable-checking=yes,extra,rtl. This adds checks to various compiler passes for integrity and input validation. This can help catch possible miscompilations early as well as latent bugs which could become real problems in future, but at the cost of slower compile times when using GCC. Unrelated to backtraces.
default-stack-clash-protection Build packages with stack clash protection on by default as a hardening measure. This enables -fstack-clash-protection by default which protects against large memory allocations allowing stack smashing. May cause slightly increased codesize, but modern compilers have been adapted to optimize well for this case, as this mitigation is now quite common. See https://developers.redhat.com/blog/2020/05/22/stack-clash-mitigation-in-gcc-part-3 and https://www.qualys.com/2017/06/19/stack-clash/stack-clash.txt.
default-znow Request full relocation on start from ld.so by default. This sets the -z,now (BIND_NOW) flag by default on all linker invocations. By resolving all dynamic symbols at application startup, parts of the program can be made read-only as a hardening measure. This is closely related to RELRO which is also separately enabled by default. In some applications with many unresolved symbols (heavily plugin based, for example), startup time may be impacted.
fixed-point Enable fixed-point arithmetic support for MIPS targets in gcc (Warning: significantly increases compile time!)
go Build the GCC Go language frontend.
graphite Add support for the framework for loop optimizations based on a polyhedral intermediate representation
ieee-long-double Use accelerated 128-bit IEEE long double ABI (ppc64le only)
jit Enable libgccjit so other applications can embed gcc for Just-In-Time compilation.
libssp Build SSP support into a dedicated library rather than use the code in the C library (DO NOT ENABLE THIS IF YOU DON'T KNOW WHAT IT DOES)
lto Build using Link Time Optimizations (LTO). Note that GCC is always built with support for building other programs with LTO. This USE flag is for whether GCC itself is built and optimized with LTO.
modula2 Build the GCC Modula-2 language frontend.
mpx Enable support for Intel Memory Protection Extensions (MPX)
nptl Enable support for Native POSIX Threads Library, the new threading module (requires linux-2.6 or better usually)
objc Build support for the Objective C code language
objc++ Build support for the Objective C++ language
objc-gc Build support for the Objective C code language Garbage Collector
pgo Build GCC using Profile Guided Optimization (PGO). GCC will build itself and then analyze the just-built binary and then rebuild itself using the data obtained from analysis of codepaths taken. It does not affect whether GCC itself supports PGO when building other software. This substantially increases the build time needed for building GCC itself.
rust Build support for the Rust language, installs gccrs.
sanitize Build support for various sanitizer functions (ASAN/TSAN/etc...) to find runtime problems in applications.
ssp Build packages with stack smashing protection on by default
systemtap enable systemtap static probe points
vtv Build support for virtual table verification (a C++ hardening feature). This does not control whether GCC defaults to using VTV> Note that actually using VTV breaks ABI and hence the whole system must be built with -fvtable-verify.

gcc-apple

bootstrap !DO NOT SET THIS FLAG YOURSELF! avoids need for autoconf during bootstrap stage2
objc Build support for the Objective C code language
objc++ Build support for the Objective C++ language

gcc-config

cc-wrappers Install and manage 'cc' and 'f77' wrappers in /usr/bin. Otherwise ignore them.
native-symlinks Install native symlinks like 'gcc' or 'g++' to /usr/bin. Otherwise keep only ${CTARGET}-gcc and friends.

gdb

cet Enable Intel Control-flow Enforcement Technology.
debuginfod Enable debuginfod support via dev-libs/elfutils libdebuginfod
lzma Support lzma compression in ELF debug info
multitarget Support all known targets in one gdb binary
python Enable support for the new internal scripting language, as well as extended pretty printers
server Install the "gdbserver" program (useful for embedded/remote targets)
sim Build gdb's simulators for various hardware platforms. See https://sourceware.org/gdb/wiki/Sim.
source-highlight Enable listing highlighting via dev-util/source-highlight
xml Support parsing XML data files needed (at least) for cpu features, memory maps, and syscall tracing
xxhash Use dev-libs/xxhash to speed up internal hashing.

gettext

git When running `autopoint`, use git to store the internal development files; this requires git at runtime, but will be faster/smaller than raw archives
multilib-symlinks Install symlinks for all ABI CHOSTs. Note that this can result in gcc being overrode for native builds, as well as conflict with crossdev if used for the same targets.
native-symlinks Install generic 'ld' symlink, as well as ${CTARGET}-ld. These symlinks are installed into slotted LLVM bindir, so they should not take precedence over symlinks installed into /usr/bin by sys-devel/binutils-config but they can be helpful for binutils-free setups.

llvm

binutils-plugin Build the binutils plugin
debuginfod Install llvm-debuginfod (requires net-misc/curl and dev-cpp/cpp-httplib)
doc Build and install the HTML documentation and regenerate the man pages
exegesis Enable performance counter support for llvm-exegesis tool that can be used to measure host machine instruction characteristics
ncurses Support querying terminal properties using ncurses' terminfo
xar Support dumping LLVM bitcode sections in Mach-O files (uses app-arch/xar)
z3 Enable support for sci-mathematics/z3 constraint solver
multilib-symlinks Install symlinks for all ABI CHOSTs. Note that this can result in gcc being overrode for native builds, as well as conflict with crossdev if used for the same targets.
native-symlinks Install generic tool symlinks like 'objdump' and 'ranlib', as well as ${CTARGET}-*. These symlinks are installed into slotted LLVM bindir, so they should not take precedence over symlinks installed into /usr/bin by sys-devel/binutils-config but they can be helpful for binutils-free setups.

sparse

gtk Build the test-inspect utility (requires x11-libs/gtk+:3)
llvm Build the sparse-llvm utility
xml Build the c2xml utility (requires dev-libs/libxml2)

sys-fabric

mstflint

adb-generic-tools Enable compiling the following tools: mstreg and mstlink
inband Enable firmware updates for Mellanox SwitchX and ConnectIB devices

opensm

tools Install ssld extra tool

sys-firmware

broadcom-bt-firmware

compress-xz Compress firmware using xz (app-arch/xz-utils) before installation
compress-zstd Compress firmware using zstd (app-arch/zstd) before installation

edk2-ovmf

binary Use pre-built binaries

intel-microcode

hostonly Only install ucode(s) supported by currently available (=online) processor(s)
initramfs Install a small initramfs for use with CONFIG_MICROCODE_EARLY
split-ucode Install the split binary ucode files (used by the kernel directly)
vanilla Only install microcode updates from Intel's official microcode tarball

ipxe

binary Use pre-built binaries
efi Build a 32bit EFI program for using PXE
efi64 Build a 64bit EFI program for using PXE
iso Build a bootable ISO for using PXE
lkrn Build a linux kernel bootable file for using with grub/etc...
qemu Build the required PXE ROM images for app-emulation/qemu
undi Build a Universal Network Device Interface driver chainloading your existing PXE NIC into iPXE
usb Build a bootable USB image for using PXE
vmware Build the PXE ROM images that VMWare uses

seabios

binary Use official upstream pre-built binaries
seavgabios Include SeaVGABIOS binaries (replacement for vgabios)

sgabios

binary Use pre-built binaries

sigrok-firmware-fx2lafw

binary Use official upstream pre-built binaries

vgabios

binary Use official upstream pre-built binaries (only default and cirrus images)

sys-fs

android-file-transfer-linux

fuse Add FUSE mount helper
zune Enable support for Microsoft Zune

avfs

webdav Allow mounting WebDAV shares via net-libs/neon

bcachefs-tools

fuse Enable bcachefs FUSE support (experimental!)

btrfs-progs

convert Build ext2 conversion utility (btrfs-convert)
reiserfs Enable reiserfs support in btrfs-convert tool.
static Build static binaries in addition to the dynamic ones

btrfsmaintenance

systemd Enable systemd services and timers instead of cron timers

cryptmount

argv0switch Default action given by progname.
cswap Enable support for encrypted swap.
fsck Check filesystems before mounting.
gcrypt Support libgcrypt-encryption of keys.
largefile Enable support for large files.
luks Enable key management via LUKS
mount Use systemd mount/umount for operations.
openssl Support openssl-encryption of keys.

cryptsetup

argon2 Enable password hashing algorithm from app-crypt/argon2
fips Enable FIPS mode restrictions
gcrypt Use dev-libs/libgcrypt crypto backend
kernel Use kernel crypto backend (mainly for embedded systems)
nettle Use dev-libs/nettle crypto backend
openssl Use dev-libs/openssl crypto backend
pwquality Use dev-libs/libpwquality for password quality checking
reencrypt Build cryptsetup-reencrypt
ssh Build cryptsetup-ssh for experimental support of token via SSH-server
urandom Use /dev/urandom instead of /dev/random

dmraid

intel-led Enable Intel LED support
led Enable LED support
mini Create a minimal binary suitable for early boot environments

dosfstools

compat Install symlinks for legacy names of the tools

e2fsprogs

cron Install e2scrub_all cron script
fuse Build fuse2fs, a FUSE file system client for ext2/ext3/ext4 file systems
tools Build extfs tools (mke2fs, e2fsck, tune2fs, etc.)

ecryptfs-utils

gpg Enable app-crypt/gnupg key module
openssl Enable dev-libs/openssl key module
pkcs11 Enable PKCS#11 (Smartcards) key module
tpm Enable support for Trusted Platform Module (TPM) using app-crypt/trousers

erofs-utils

fuse Builds erofsfuse (requires sys-fs/fuse).
uuid Enables UUID support via sys-apps/util-linux.

ext4magic

expert-mode Builds ext4magic with expert mode. Highly useful in recovering data from a corrupted filesystem
file-attr Enable the recovery of file attributes (append, immutable, nodump etc)

lessfs

filelog Enable the ability to log to a file instead of syslog
memtrace Enable leefs to create a report regarding the memory allocation. This feature should be used for debugging purposes to avoid performance degradation

loop-aes

extra-ciphers Enable extra ciphers
keyscrub Protects the encryption key in memory but takes more cpu resources

lvm2

lvm Build all of LVM2 including daemons and tools like lvchange, not just the device-mapper library (for other packages to use). If your system uses LVM2 for managing disks and partitions, enable this flag.
sanlock Enable lvmlockd with support for sanlock
thin Support for thin volumes

mtpfs

mad Enable handling of MP3's metadata

ntfs3g

fuse Enable ntfs-3g FUSE driver
mount-ntfs Install mount.ntfs symlink
ntfsdecrypt Build and install the ntfsdecrypt application.
ntfsprogs Enable ntfsprogs

quota

netlink Compile daemon receiving quota messages via netlink
rpc Enable quota interaction via RPC

squashfs-tools-ng

tools Build the gensquashfs, rdsquashfs, sqfs2tar, sqfsdiff, and tar2sqfs tools

udisks

daemon Build the system daemon, not just the client tool
elogind Use sys-auth/elogind for session tracking
lvm Add support for Logical Volume Management via sys-fs/lvm2.
systemd Support sys-apps/systemd's logind
vdo Enable Virtual Data Optimizer support.
zram Enable ZRAM support (requires sys-apps/systemd).

zfs

kernel-builtin Disable dependency on sys-fs/zfs-kmod under the assumption that ZFS is part of the kernel source tree
minimal Don't install python scripts (arcstat, dbufstat etc) and avoid dependency on dev-lang/python
pam Install zfs_key pam module, for automatically loading zfs encryption keys for home datasets
rootfs Enable dependencies required for booting off a pool containing a rootfs
test-suite Install regression test suite

zfs-auto-snapshot

cron Install /etc/cron.* files
default-exclude Only take snapshots of datasets with com.sun:auto-snapshot=true property set

zfs-kmod

dist-kernel-cap Prevents upgrading to an unsupported kernel version when combined with USE=dist-kernel
rootfs Pull dependencies and check kernel options required for root-on-zfs

sys-kernel

genkernel

firmware Prefer system firmware sys-kernel/linux-firmware over local copy.

gentoo-kernel

hardened Use selection of hardening options recommended by Kernel Self Protection Project
initramfs Build initramfs along with the kernel.

gentoo-kernel-bin

initramfs Build initramfs along with the kernel.

gentoo-sources

experimental Apply experimental patches; for more information, see "https://wiki.gentoo.org/wiki/Project:Kernel/Experimental".

installkernel-gentoo

grub Re-generate grub.cfg on each kernel installation

kpatch

contrib Enable contrib kpatch services files.
kmod Enable a kernel module (.ko file) which provides an interface for the patch modules to register new functions for replacement.
kpatch Enable a command-line tool which allows a user to manage a collection of patch modules.
kpatch-build Enable tools which convert a source diff patch to a patch module.

linux-firmware

compress-xz Compress firmware using xz (app-arch/xz-utils) before installation
compress-zstd Compress firmware using zstd (app-arch/zstd) before installation
initramfs Create and install initramfs for early microcode loading in /boot (only AMD for now)
redistributable Install also non-free (but redistributable) firmware files
savedconfig Allows individual selection of firmware files
unknown-license Install firmware files whose license is unknown

mips-sources

experimental Apply experimental (80xx) patches.
ip27 Enables additional support for SGI Origin (IP27)
ip28 Enables additional support for SGI Indigo2 Impact R10000 (IP28)
ip30 Enables support for SGI Octane (IP30, 'Speedracer')

rt-sources

deblob Remove binary blobs from kernel sources to provide libre license compliance.

vanilla-kernel

initramfs Build initramfs along with the kernel.

sys-libs

binutils-libs

64-bit-bfd Support 64-bit targets even on 32-bit hosts (is ignored on 64-bit hosts)
cet Enable Intel Control-flow Enforcement Technology.
multitarget Enable all possible targets in libbfd

compiler-rt

clang Force building using installed clang (rather than the default CC/CXX).

compiler-rt-sanitizers

asan Build Address Sanitizer runtime.
cfi Build Control Flow Integrity runtime.
clang Force building using installed clang (rather than the default CC/CXX).
dfsan Build Data Flow Sanitizer runtime.
gwp-asan Build GWP-ASAN runtime.
hwasan Build Hardware ASAN runtime.
libfuzzer Build fuzzing runtime.
lsan Build Leak Sanitizer runtime.
memprof Build memory profiler runtime.
msan Build Memory Sanitizer runtime.
orc Build ORC runtime.
profile Build profiling runtime.
safestack Build SafeStack runtime.
scudo Build Scudo Hardened Allocator.
shadowcallstack Build ShadowCallStack.
tsan Build Thread Sanitizer runtime.
ubsan Build Undefined Behavior Sanitizer runtime.
xray Build XRay runtime.

freeipmi

nagios Install a nagios plugin to check sensors' status.
without-root Configure whether or not to check for root access in ipmi tools.

gdbm

berkdb enable compatibility layer for UNIX-like dbm and ndbm interfaces

glibc

cet Enable Intel Control-flow Enforcement Technology (needs binutils 2.29 and gcc 8)
clone3 Enable the new clone3 syscall within glibc. Can be disabled to allow compatibility with older Electron applications.
compile-locales build *all* locales in src_install; this is generally meant for stage building only as it ignores /etc/locale.gen file and can be pretty slow
crypt build and install libcrypt and crypt.h
debug When USE=hardened, allow fortify/stack violations to dump core (SIGABRT) and not kill self (SIGKILL)
experimental-loong Add experimental LoongArch patchset
gd build memusage and memusagestat tools
hash-sysv-compat enable sysv linker hashes in glibc for compatibility with binary software (EAC via wine/proton)
multiarch enable optimizations for multiple CPU architectures (detected at runtime)
multilib-bootstrap Provide prebuilt libgcc.a and crt files if missing. Only needed for ABI switch.
nscd Build, and enable support for, the Name Service Cache Daemon
perl Install additional scripts written in Perl
ssp protect stack of glibc internals
stack-realign Realign the stack in the 32-bit build for compatibility with older binaries at some performance cost
static-pie Enable static PIE support (runtime files for -static-pie gcc option).
suid Make internal pt_chown helper setuid -- not needed if using Linux and have /dev/pts mounted with gid=5
systemtap enable systemtap static probe points

ldb

doc Builds documentation
ldap Enable LDAP support
lmdb Enable LMDB backend
python Enable Python support

libblockdev

bcache Enable block device cache support.
cryptsetup Enable sys-fs/cryptsetup support
device-mapper Enable support for device-mapper from sys-fs/lvm2
dmraid Support for dmraid devices, also known as ATA-RAID, or Fake RAID.
escrow Support for building crypto plugin with escrow device support
kbd Enable kernel block device support.
lvm Enable support for Logical Volume Management via sys-fs/lvm2.
nvme Add nvme support via sys-libs/libnvme
tools Build tools
vdo Enable Virtual Data Optimizer support.

libcap

tools Install captree, which requires dev-lang/go

libcxx

clang Force building using installed clang (rather than the default CC/CXX; required for testing).
libcxxabi Build on top of sys-libs/libcxxabi instead of gcc's libsupc++ (avoids depending on gcc).
libunwind Use libunwind instead of libgcc_s for stack unwinding, thus avoiding dependence on gcc.

libcxxabi

clang Force building using installed clang (rather than the default CC/CXX; required for testing).
libunwind Use libunwind instead of libgcc_s for stack unwinding, thus avoiding dependency on gcc

libnbd

fuse Install the sys-fs/fuse powered nbdfuse.
go Build bindings for dev-lang/go
uri-support Enable nbd:// URI support via dev-libs/libxml2.

libnvme

json Support JSON output via dev-libs/json-c
keyutils Add support for sys-apps/keyutils
uuid UUID support via sys-apps/util-linux

libomp

cuda Build CUDA offloading plugin (only with USE=offload)
gdb-plugin Build OMPD GDB plugin
hwloc Enable CPU affinity support via hwloc
offload Support offloading OpenMP using libomptarget
ompt Enable OpenMP Tools Interface support

libseccomp

experimental-loong Add experimental LoongArch patchset

libunwind

debug-frame Adds support for DWARF .debug_frame section: Use the information from this section if available
libatomic Use libatomic instead of builtin atomic operations

libxcrypt

compat Build with compatibility interfaces for other crypt implementations
headers-only Build and install only the headers.
system Install as system libcrypt.so rather than to an alternate directory (will collide with sys-libs/glibc's version)

llvm-libunwind

clang Force building using installed clang (rather than the default CC/CXX; required for testing).

minizip-ng

compat Enable compatibility with sys-libs/zlib's USE=minizip
openssl Use dev-libs/openssl for further encryption capabilities

musl-nscd

minimal Only installs the header files

ncurses

ada Add bindings for the ADA programming language
stack-realign Realign the stack in the 32-bit build for compatibility with older binaries at some performance cost. Avoids crashes in older 32-bit binaries. Only affects x86/32-bit multilib builds on amd64.
tinfo Build curses library (libncurses) sep from the low-level terminfo library (libtinfo) -- usually needed only for binary packages -- but it is binary compatible in either mode
trace Enable test trace() support in ncurses calls

ncurses-compat

stack-realign Realign the stack in the 32-bit build for compatibility with older binaries at some performance cost. Avoids crashes in older 32-bit binaries. Only affects x86/32-bit multilib builds on amd64.
tinfo Build curses library (libncurses) sep from the low-level terminfo library (libtinfo) -- usually needed only for binary packages -- but it is binary compatible in either mode

newlib

nano Build additional newlib-nano library

pam

berkdb Build the pam_userdb module, that allows to authenticate users against a Berkeley DB file. Please note that enabling this USE flag will create a PAM module that links to the Berkeley DB (as provided by sys-libs/db) installed in /usr/lib and will thus not work for boot-critical services authentication.

readline

utils Install rlfe (ReadLine Front-End) helper tool -- a wrapper program for making any stdin use readline

snapd-glib

qml Build the QML bindings

talloc

compat Enable extra compatibility stuff

timezone-data

leaps-timezone Install the set of "right" timezones; these timezones include leap seconds when counting seconds since the epoch (while POSIX does not) as they are based on the TAI (International Atomic Time) clock
zic-slim Default to 'slim' file format for /usr/share/zoneinfo. Otherwise 'fat' format is used. Not all programs can handle 'slim' format'.

zlib

minizip include the minizip library for quick and dirty zip extraction

zlib-ng

compat Enable compatibility to sys-libs/zlib

sys-power

apcupsd

modbus Enable MODBUS support over USB

autosuspend

mpd Enable support for the Music Player Daemon

intel-undervolt

elogind Use elogind hook to apply voltage after system sleep

nut

gpio Includes all UPS drivers that use GPIO.
i2c Includes all UPS drivers that use I2C.
ipmi Includes all UPS drivers that use ipmi.
modbus Includes all UPS drivers that use MODBUS.
monitor Add a QT5 gui monitor.
serial Includes all UPS drivers that use SERIAL.
snmp Includes all UPS drivers that use SNMP.
ups_drivers_al175 Driver for Eltek UPS models with AL175 alarm module
ups_drivers_apcsmart Driver for American Power Conversion Smart Protocol UPS equipment
ups_drivers_apcsmart-old Driver for American Power Conversion Smart Protocol UPS equipment
ups_drivers_apcupsd-ups Driver for apcupsd client access
ups_drivers_bcmxcp Driver for UPSes supporting the serial BCM/XCP protocol
ups_drivers_bcmxcp_usb Experimental driver for UPSes supporting the BCM/XCP protocol over USB
ups_drivers_belkin Driver for Belkin serial UPS equipment
ups_drivers_belkinunv Driver for Belkin "Universal UPS" and compatible
ups_drivers_bestfcom Driver for Best Power Fortress/Ferrups
ups_drivers_bestfortress Driver for old Best Fortress UPS equipment
ups_drivers_bestuferrups Driver for Best Power Micro-Ferrups
ups_drivers_bestups Driver for Best Power / SOLA (Phoenixtec protocol) UPS equipment
ups_drivers_blazer_ser Driver for Megatec/Q1 protocol serial based UPS equipment
ups_drivers_blazer_usb Driver for Megatec/Q1 protocol USB based UPS equipment
ups_drivers_clone Fake driver to clone outlets for device grouping
ups_drivers_clone-outlet Fake driver to clone outlets for device grouping
ups_drivers_dummy-ups Driver for multi-purpose UPS emulation
ups_drivers_etapro Driver for ETA UPS equipment
ups_drivers_everups Driver for Ever UPS models
ups_drivers_gamatronic Driver for Gamatronic UPS equipment
ups_drivers_genericups Driver for contact-closure UPS equipment
ups_drivers_isbmex Driver for ISBMEX UPS equipment
ups_drivers_ivtscd driver for the IVT Solar Controller Device
ups_drivers_liebert Driver for Liebert contact-closure UPS equipment
ups_drivers_liebert-esp2 Driver for Liebert UPS, using the ESP-II serial protocol
ups_drivers_masterguard Driver for Masterguard UPS equipment
ups_drivers_metasys Driver for Meta System UPS equipment
ups_drivers_mge-shut Driver for SHUT Protocol UPS equipment
ups_drivers_mge-utalk Driver for MGE UPS SYSTEMS UTalk protocol equipment
ups_drivers_microdowell Driver for Microdowell Enterprise UPS series
ups_drivers_netxml-ups Driver for Eaton / MGE Network Management Card / Proxy (XML/HTTP Protocol) equipment
ups_drivers_nut-ipmipsu Driver for IPMI Power Supply Units (PSU)
ups_drivers_nutdrv_qx Driver for Q* protocol serial and USB based UPS equipment
ups_drivers_oldmge-shut Driver for SHUT Protocol UPS equipment (older implementation)
ups_drivers_oneac Driver for Oneac UPS equipment
ups_drivers_optiups Driver for Opti-UPS (Viewsonic) UPS and Zinto D (ONLINE-USV) equipment
ups_drivers_powercom UPS driver for serial Powercom/Trust/Advice UPS equipment
ups_drivers_powerpanel Driver for PowerPanel Plus compatible UPS equipment
ups_drivers_rhino Driver for Brazilian Microsol RHINO UPS equipment
ups_drivers_richcomm_usb Driver UPS equipment using Richcomm dry-contact to USB solution
ups_drivers_riello_ser Driver for Riello UPS Protocol UPS equipment
ups_drivers_riello_usb Driver for Riello UPS Protocol UPS equipment via USB
ups_drivers_safenet Driver for SafeNet compatible UPS equipment
ups_drivers_snmp-ups Multi-MIB Driver for SNMP UPS equipment
ups_drivers_solis Driver for Brazilian Microsol SOLIS UPS equipment
ups_drivers_tripplite Driver for Tripp-Lite SmartPro UPS equipment
ups_drivers_tripplite_usb Driver for older Tripp Lite USB UPSes (not PDC HID)
ups_drivers_tripplitesu Driver for Tripp-Lite SmartOnline (SU) UPS equipment
ups_drivers_upscode2 Driver for UPScode II compatible UPS equipment
ups_drivers_usbhid-ups Driver for USB/HID UPS equipment
ups_drivers_victronups Driver for IMV/Victron UPS unit Match, Match Lite, NetUps
usb Includes all UPS drivers that use USB.
xml Includes all UPS drivers that use XML.

nvclock

gtk Install the GTK+ based graphical interface
nvcontrol Add NVCONTROL support for OpenGL options

suspend

crypt Allows suspend and resume from encrypted disk

sys-process

atop

modules Build netatop kernel module and install netatopd daemon.

audit

gssapi Enable GSSAPI support
io-uring Enable support for io-uring. Doesn't need the library but needs at least kernel 5.1.

bottom

battery Include support for laptop battery information
gpu Include support for GPU temperature and memory usage information
zfs Include support for ZFS ARC memory usage information

criu

bpf Add support for BPF programs via dev-libs/libbpf
nftables Add support for net-firewall/nftables
setproctitle Use dev-libs/libbsd to make process titles of service workers to be more verbose

cronie

anacron Install the periodic anacron command scheduler.

fcron

debug Enable debug code and output. Since version 3.0.5 this will no longer force foreground execution, and fcron will be able to run as a service properly.
mta Enable mta support for sending emails from fcron
pam Enable PAM support for fcron. This means that fcron will pass through the "fcron" stack before executing the jobs, and fcrontab will use the "fcrontab" stack to authenticate the user before editing its crontab file.
system-crontab Set up fcron to respect /etc/crontab and /etc/cron.d. If this flag is disabled, /etc/cron.d and /etc/crontab will be ignored, but /etc/cron.{hourly,daily,weekly,monthly} will still be respected. Also this creates /usr/bin/crontab symlink.

htop

delayacct Enable Linux delay accounting support via dev-libs/libnl
hwloc Use sys-apps/hwloc for CPU affinity support
openvz Enable openvz support
vserver Enable vserver support

lsof

rpc support looking up RPC service info

procps

elogind Use sys-auth/elogind for session tracking.
kill Build the kill program
modern-top Enables new startup defaults of top. Keeps old defaults if disabled
ncurses Build programs that use ncurses: top, slabtop, watch

systemd-cron

cron-boot Include support for the boot timer.
etc-crontab-systemd Use dedicated /etc/crontab-systemd instead of parsing /etc/crontab
minutely Support /etc/cron.minutely
runparts Use traditional run-parts instead of creating jobs for each cron.* entry
setgid Compile setgid C helper for crontab. Needs GCC or Clang.
yearly Support /etc/cron.yearly

tini

args Enable argument parsing.

virtual

blas

eselect-ldso Enable runtime library switching by eselect and ld.so.

cblas

eselect-ldso Enable runtime library switching by eselect and ld.so.

jdk

headless-awt Don't install the X backend for AWT, needed by some GUIs

lapack

eselect-ldso Enable runtime library switching by eselect and ld.so.

lapacke

eselect-ldso Enable runtime library switching by eselect and ld.so.

linux-sources

firmware Install linux kernel firmware

mpi

nullmpi Allow sys-cluster/nullmpi a minimal incomplete MPI implementation as a provider
romio Enable romio, a high-performance portable MPI-IO

mysql

embedded Build embedded server (libmysqld)
server Build server (mysqld)

podofo-build

boost Add support for boost
tools Build and install commandline tools

rust

rustfmt Install rustfmt, Rust code formatter

ssh

minimal Prefer net-misc/dropbear over net-misc/openssh

wine

proton Enable Valve Software's fork of Wine
staging Enable Wine-Staging's Patchset

www-apache

mod_backtrace

unwind Use sys-libs/libunwind to provide better resolution of function names.

mod_musicindex

archive Add archive support
cache Add File cache support
mysql Add MySQL cache support

mod_nss

ecc enable Elliptical Curve Cyptography

mod_perl

ithreads Build for use with thread-capable perl, needs same setting as in dev-lang/perl

mod_security

fuzzyhash Support fuzzy hash computations (to detect malware, for example) using the app-crypt/ssdeep package.
geoip Pull in dev-libs/geoip for use by the SecGeoLookupDb directive.
jit Add support for the PCRE Just-in-Time optimisation, as enabled by dev-libs/libpcre with jit USE flag enabled. Might not be available on hardened systems.
json Suppose JSON in the request body parser through dev-libs/yajl.
mlogc Build and install the ModSecurity Audit Log Collector (mlogc).
pcre2 Use dev-libs/libpcre2 as regex implementation

pwauth

domain-aware Ignore leading domain names in username (Windows compat)
faillog Log failed login attempts
ignore-case Ignore string case in username (mostly Windows compat)

www-apps

cgit

highlight Enable source code highlighting
lua Enable support for Lua scripting

drupal

uploadprogress Install dev-php/pecl-uploadprogress package

gitea

acct User and group management via acct-*/git packages

hugo

sass Enable SASS/SCSS support

icingaweb2

apache2-server Adds support for the apache2-server
fpm Adds FPM support to php
nginx Adds support for nginx

ikiwiki

extras Installs additional modules used by ikiwiki plugins

klaus

ctags Enable support for Exuberant ctags; makes all source code symbols hyperlinks to their definitions

postfixadmin

vacation Install vacation.pl script and dependencies

redmine

markdown Enable support for Markdown
minimagick Enable image processing support via dev-ruby/mini_magick
passenger Enable support for www-apache/passenger
standalone Enable standalone mode with www-servers/puma

roundup

jinja Enable Jinja2 support
markdown Enable markdown rendering
pyjwt Enable jwt tokens for login
tz Enable full support of timezone
whoosh Enable Whoosh full-text indexer
xapian Enable Xapian full-text indexer

rt

lighttpd Add www-servers/lighttpd support

tt-rss

daemon Install additional init scripts for automated RSS updates

webdavcgi

rcs Adds support for a revision controlled backend with RCS (dev-vcs/rcs)

wordpress

akismet Installs Akismet comment spam plug-in
themes Installs themes (including default theme)

xpra-html5

brotli Install assets compressed with brotli
gzip Install assets compressed with gzip
minify Minify JavaScript code for smaller transfers

www-client

chromium

debug Enable DCHECK feature with severity configurable at runtime. Mostly intended for debugging and development, NOT RECOMMENDED for general use.
gtk4 Build with GTK4 headers.
hangouts Enable support for Google Hangouts features such as screen sharing
headless Build Ozone only with headless backend, NOT RECOMMENDED for general use.
libcxx Use bundled libc++ instead of libstdc++ for building.
lto Build with Link Time Optimizations (via clang's ThinLTO)
official Enable Official build instead of Developer build.
pax-kernel Allow building on a PaX-enabled kernel
pgo Build with Profile Guided Optimizations (2-stage compilation)
proprietary-codecs Enable codecs for patent-encumbered audio and video formats.
system-harfbuzz Use system media-libs/harfbuzz instead of the bundled library.
system-icu Use system dev-libs/icu instead of the bundled one
system-png Use system media-libs/libpng instead of the bundled library
system-zstd Use system app-arch/zstd instead of the bundled one.
widevine Unsupported closed-source DRM capability (required by Netflix VOD)
bittorrent Enable support for the BitTorrent protocol
finger Enable support for the finger protocol
gopher Enable support for the gopher protocol
mouse Make elinks to grab all mouse events
tre Enable support for regex searches via dev-libs/tre
xml Enable support for bookmarks via dev-libs/expat

firefox

clang Use Clang compiler instead of GCC
eme-free Disable EME (DRM plugin) capability at build time
geckodriver Enable WebDriver support
gmp-autoupdate Allow Gecko Media Plugins (binary blobs) to be automatically downloaded and kept up-to-date in user profiles
hwaccel Force-enable hardware-accelerated rendering (Mozilla bug 594876)
jumbo-build Enable unified build - combines source files to speed up build process, but requires more memory
libproxy Enable libproxy support
lto Enable Link Time Optimization (LTO)
openh264 Use media-libs/openh264 for H264 support instead of downloading binary blob from Mozilla at runtime
pgo Add support for profile-guided optimization for faster binaries - this option will double the compile time
pulseaudio Add sound server support via media-libs/libpulse (may be PulseAudio or Pipewire, or apulse if installed)
sndio Enable support for the media-sound/sndio backend
system-av1 Use the system-wide media-libs/dav1d and media-libs/libaom library instead of bundled
system-harfbuzz Use the system-wide media-libs/harfbuzz and media-gfx/graphite2 instead of bundled
system-icu Use the system-wide dev-libs/icu instead of bundled
system-jpeg Use the system-wide media-libs/libjpeg-turbo instead of bundled
system-libevent Use the system-wide dev-libs/libevent instead of bundled
system-libvpx Use the system-wide media-libs/libvpx instead of bundled
system-png Use the system-wide media-libs/libpng instead of bundled (requires APNG patches)
system-python-libs Use system's python site instead of bundled python libraries
system-webp Use the system-wide media-libs/libwebp instead of bundled
wifi Enable necko-wifi for NetworkManager integration, and access point MAC address scanning for better precision with opt-in geolocation services

firefox-bin

alsa When pulseaudio isn't set, this prefers apulse
gmp-autoupdate Allow Gecko Media Plugins (binary blobs) to be automatically downloaded and kept up-to-date in user profiles

jd

migemo Enable migemo support for Japanese
oniguruma Use dev-libs/oniguruma for regular expression
freetype Enable media-libs/freetype support
libevent Enable dev-libs/libevent support

lynx

gnutls Use gnutls library for HTTPS support (openssl is the default library for HTTPS support).
ssl Enable HTTPS support.

microsoft-edge

mip Install Microsoft Information Protection plugin.

microsoft-edge-beta

mip Install Microsoft Information Protection plugin.

microsoft-edge-dev

mip Install Microsoft Information Protection plugin.

netsurf

bmp Bitmap (BMP and ICO) image support via media-libs/libnsbmp
gtk Build GTK3 GUI
psl Use public suffix list from media-libs/libnspsl to detect supercookies (recommended)
rosprite RISC OS Sprite bitmap image support via media-libs/librosprite
svgtiny Use media-libs/libsvgtiny instead of gnome-base/librsvg for SVG support
truetype Use media-libs/freetype for text in the framebuffer frontend

opera

proprietary-codecs Enable codecs for patent-encumbered audio and video formats.

opera-beta

proprietary-codecs Enable codecs for patent-encumbered audio and video formats.

opera-developer

proprietary-codecs Enable codecs for patent-encumbered audio and video formats.

qutebrowser

adblock Enable Brave's ABP-style adblocker library for improved adblocking
qt6 Use Qt6 that provides a newer Chromium version
widevine Unsupported closed-source DRM capability (required by Netflix VOD)

seamonkey

chatzilla Build Mozilla's IRC client (default on)
custom-optimization Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS (unsupported)
gmp-autoupdate Allow Gecko Media Plugins (binary blobs) to be automatically downloaded and kept up-to-date in user profiles
ipc Use inter-process communication between tabs and plugins. Allows for greater stability in case of plugin crashes
lto Enable Link Time Optimization (LTO). Requires Gold linker
system-av1 Use the system-wide media-libs/dav1d and media-libs/libaom library instead of bundled
system-harfbuzz Use the system-wide media-libs/harfbuzz instead of bundled
system-icu Use the sytem-wide dev-libs/icu instead of bundled
system-jpeg Use the system-wide media-libs/libjpeg-turbo instead of bundled
system-libevent Use the system-wide dev-libs/libevent instead of bundled
system-libvpx Use the system-wide media-libs/libvpx instead of bundled
system-png Use the system-wide media-libs/libpng instead of bundled (requires APNG patches)
system-sqlite Use the system-wide dev-db/sqlite installation with secure-delete enabled
webrtc Enable WebRTC support. Disabled by default due to privacy concerns.

surf

savedconfig Without a saved config.h, this package depends on net-misc/curl and x11-terms/st for a default download mechanism
tabbed Install surf-open.sh script for running surf in x11-misc/tabbed

uget

aria2 Enable support for net-misc/aria2 through xmlrpc. You'll find the plugin in the app's settings.
control-socket Enable JSON-RPC over unix domain socket
openssl Use dev-libs/openssl instead of net-libs/gnutls
rss Enable uGet feed messages

vivaldi

proprietary-codecs Use system media-video/ffmpeg to support patent-encumbered media codecs
widevine Unsupported closed-source DRM capability (required by Netflix VOD)

vivaldi-snapshot

proprietary-codecs Use system media-video/ffmpeg to support patent-encumbered media codecs
widevine Unsupported closed-source DRM capability (required by Netflix VOD)

w3m

gdk-pixbuf Enable support for x11-libs/gdk-pixbuf
lynxkeymap If you prefer Lynx-like key binding

www-misc

litmus

libproxy Support for automatic proxy configuratino management through net-libs/libproxy.
libxml2 Use dev-libs/libxml2 to parse XML
pkcs11 Support for PKCS #11 through PaKChoiS (dev-libs/pakchois).

www-plugins

lightspark

ppapi Install the PPAPI plugin (for Chromium)
rtmp Enable Real Time Messaging Protocol using librtmp

passff-host

chrome Install plugin for chrome (which also includes opera)
chromium Install plugin for chromium
firefox Install plugin for firefox
vivaldi Install plugin for vivaldi

www-servers

apache

static Link in apache2 modules statically rather then plugins
suexec Install suexec with apache
suexec-caps Install suexec with capabilities instead of SUID
suexec-syslog Log suexec to syslog instead of to a separate file

civetweb

server Build standalone server

fnord

auth Enable HTTP authentication support

gatling

diet Compile against dev-libs/dietlibc

h2o

libh2o Build and install libh2o
mruby Enable support for mruby

kore

acme Add support for ACME
http Add support for HTTP
json Add support for JSONRPC
openssl Use the openssl TLS backend

lighttpd

brotli Enable output compression via app-arch/brotli (recommended)
gnutls Build module for TLS via net-libs/gnutls
maxminddb Add support for geolocation using dev-libs/libmaxminddb
mbedtls Build module for TLS via net-libs/mbedtls
mmap Use mmap when sendfile is not available
nettle Use dev-libs/nettle as crypto backend
nss Build module for TLS via Mozilla's Network Security Services
rrdtool Enable rrdtool support via mod_rrdtool
system-xxhash Use system provided dev-libs/xxhash
webdav Enable webdav properties
zlib Enable output compression via gzip or deflate algorithms from sys-libs/zlib
zstd Enable output compression via Zstandard (app-arch/zstd) algorithm

monkeyd

debug Enable lots of debugging info
static-plugins Build statically linked plugins

nginx

aio Enables file AIO support
http Enable HTTP core support
http-cache Enable HTTP cache support
http2 Enable HTTP2 module support
http3 Enable HTTP3 module support
ktls Enable Kernel TLS offload (kTLS)
libatomic Use libatomic instead of builtin atomic operations
pcre-jit Enable JIT for pcre
pcre2 Enable support for pcre2
rtmp NGINX-based Media Streaming Server
ssl Enable HTTPS module for http. Enable SSL/TLS support for POP3/IMAP/SMTP for mail.

nginx-unit

php8-1 Support for PHP 8.1
php8-2 Support for PHP 8.2

pshs

magic Enable automatic detection of Content-Type using libmagic (sys-apps/file)
qrcode Enable generating QRCodes for server URL

sniproxy

dns Enable DNS resolver via net-libs/udns
largefile Enable large file support (so we can log more than 2GB)
rfc3339 Use RFC3339 timestamp format in log.

tomcat

extra-webapps Build also the docs and examples webapp

uwsgi

embedded Embed plugins instead of building them as real plugins. When disabling this USE flag make sure you specify all used plugins in your uWSGI configuration. Note: Language plugins will always be built as real plugins.
go Build the gccgo plugin to run Go applications.
json Support json as a configuration file format.
python-asyncio Use the EXPERIMENTAL asyncio (tulip) for python3.4 async request dispatching and as LoopEngine (see http://uwsgi-docs.readthedocs.org/en/latest/asyncio.html).
routing Enable routing support
yajl Use dev-libs/yajl instead of dev-libs/jansson for parsing JSON configuration files (if USe=json is set)
yaml Support yaml as a configuration file format.
zeromq Enable logging and deployment via ZeroMQ.

xsp

developer creates .mdb files for either Release and Debug
net35 use .NET 3.5 Framework
net40 use .NET 4.0 Framework
net45 use .NET 4.5 Framework

x11-apps

igt-gpu-tools

X Enable intel-gpu-overlay xlib/cairo backend
chamelium Enables support for building Chamelium tests
overlay Build the intel-gpu-overlay utility
runner Build the test runner
tests Build and install tests
xv Enable intel-gpu-overlay xv backend

mesa-progs

gles2 Build OpenGL ES 2 utilities

xdpyinfo

dmx Builds support for Distributed Multiheaded X x11-base/xorg-server

xinit

twm Control dependencies on legacy apps (xterm, twm, ...). Safe to disable if you use a modern desktop environment.

x11-base

xorg-server

elogind Use elogind to get control over framebuffer when running as regular user
unwind Enable libunwind usage for backtraces
xcsecurity Build Security extension
xephyr Build the Xephyr server
xnest Build the Xnest server
xorg Build the Xorg X server (HIGHLY RECOMMENDED)
xvfb Build the Xvfb server

xwayland

libei Enable emulated input using dev-libs/libei
unwind Enable libunwind usage for backtraces
xcsecurity Build Security extension

x11-drivers

nvidia-drivers

kernel-open Use the open source variant of drivers (Turing/Ampere+ GPUs only, aka GTX 1650+, experimental)
persistenced Install the persistence daemon for keeping devices state when unused (e.g. for headless)
static-libs Install the XNVCtrl static library for accessing sensors and other features
tools Install additional tools such as nvidia-settings

xf86-video-geode

ztv Enable building the V4L2 ZTV driver

xf86-video-intel

sna Enable SandyBridge's New Acceleration (useful on all chipsets, not just SandyBridge)
tools Build the intel-virtual-output tool
uxa Enable UMA Acceleration Architecture
xvmc Enables X-Video Motion Compensation support

xf86-video-openchrome

viaregtool Install registers dumper tool

xf86-video-qxl

xspice Include Xspice, a standard X server that is also a Spice server

x11-libs

agg

gpc Enable gpc polygon clipper library

cairo

glib Compile with GLib Object System support

fltk

games Builds and installs some extra games

fox

tools Install adie, calculator, shutterbug, and pathfinder apps.

gtk+

broadway Enable the GDK Broadway backend
cloudproviders Enable GtkPlacesSidebar to access cloud services
colord Use x11-misc/colord for color management in printing
sysprof Enable profiling data capture support using dev-util/sysprof-capture

gtkdatabox

glade Build with libglade and glade-3 supports, which includes a glade's module for GtkDataBox widget

gtkmathview

mathml Install additional fonts for proper mathml support.
t1lib Enable media-libs/t1lib support

gtksourceview

glade Install a glade catalog file

libQGLViewer

designer Installs dev-qt/designer plugin.

libSM

uuid Use UUID for session identification instead of IP address and system time.

libXaw

deprecated Install deprecated Xaw6 library.

libXfont2

bzip2 Support bzip2 compressed PCF fonts.
truetype Use media-libs/freetype for font rasterization.

libdlo

test-program Build the program for testing Displaylink devices.

libfm

automount Use gnome-base/gvfs for automounting
udisks Use libfm's udisks-based volume monitor implementation instead of using the one from gvfs
vala Support custom actions in menus

libwnck

tools Install wnckprop-3 and wnck-urgency-monitor-3 command-line tools

libxcb

xkb Enable the XCB keyboard extension

libxkbcommon

tools Build the xkbcli tools

motif

motif22-compatibility Compatibility with Open Motif 2.2

pango

X Build and install the legacy pangoxft library
sysprof Enable profiling data capture support using dev-util/sysprof-capture

pixman

loongson2f Enable Loongson2f MMI optimizations.

qscintilla

designer Build plugin for Qt Designer

qwt

designer Installs dev-qt/designer plugin.
mathml Use the MathML renderer of the Qt solutions package.
polar Install the QwtPolar headers

tslib

evdev Build experimental input module
uinput Provide alternative ts_uinput evdev device

vte

icu Enable legacy charset support using dev-libs/icu
systemd Support moving terminal child processes to their own systemd user scopes to avoid terminal getting killed due to child causing OOM

wxGTK

gstreamer Enable the wxMediaCtrl class for playing audio and video through gstreamer.
sdl Use Simple Directmedia Layer (media-libs/libsdl) for audio.

xapp

mate Install status applet for mate-base/mate

x11-misc

albert

debug Enable debugging informations
python-extensions Install default python extensions system-wide
statistics Enable local statistics
virtualbox Enable app-emulation/virtualbox extension

alock

doc Build and install manpage with app-text/asciidoc.

appmenu-gtk-module

gtk2 Build module for GTK+2

autorandr

launcher Install the launcher, i.e., an alternative to the udev/systemd hooks

bumblebee

bbswitch Add dependency on sys-power/bbswitch for PM feature

clipmenu

dmenu Use dmenu as default launcher
fzf Use fzf as default launcher
rofi Use rofi as default launcher

colord

argyllcms Enable ArgyllCMS sensor
extra-print-profiles Generate extra print profiles. Warning: significant build time and memory requirements.

fbpager

xrender Enable transparency support via x11-libs/libXrender

gammastep

geoclue Control dependency on app-misc/geoclue

gmrun

xdg Enable xdg spec for configuration and history files location

gpaste

gnome Enable proper gnome support and enable gnome shell extension.

grsync

gtk3 Link against x11-libs/gtk+:3 instead of x11-libs/gtk+:2

i3blocks

contrib Install contrib modules

i3status

filecaps Linux capabilities library is required for i3status to be able to read net bandwidth

j4-dmenu-desktop

dmenu Use x11-misc/dmenu as default. Disable to use a different implementation.

ktsuss

sudo Use the sudo backend instead the su one

light-locker

dpms Turn on the display on screensaver deactivation.
screensaver Lock the screen on screensaver activation.

lightdm

gtk Pull in the gtk+ greeter
non-root Use non-root user by default

mugshot

gnome Add support for gnome-base/gnome-control-center
libreoffice Add support for app-office/libreoffice and app-office/libreoffice-bin
webcam Add support for setting a profile photo in media-video/cheese

openbox-menu

icons Enable support for icons in menus
svg Support SVG icons

picom

config-file Enable config file support
doc Build documentation and man pages (requires app-text/asciidoc)
drm Enable support for using drm for vsync
opengl Enable features that require opengl (opengl backend, and opengl vsync methods)

polybar

i3wm Add support for i3 window manager
ipc Add support for Inter-Process Messaging
mpd Add support for Music Player Daemon
network Enable network support

primus

libglvnd Use media-libs/libglvnd for dispatch

py3status

minimal Don't depend on x11-misc/i3status if you don't plan to use any of its built-in modules.
udev Install extra requirement dev-python/pyudev to enable udev events monitoring on modules.

qtfm

dbus Install the qtfm-tray removable device manager
shared Install the libQtFM shared library and headers

read-edid

vbe-mode Build get-edid with support for legacy, VBE-based interface. Requires dev-libs/libx86.

redshift

geoclue Control dependency on app-misc/geoclue

rofi

drun Enable desktop file run dialog
windowmode Enable normal window mode

rss-glx

quesoglc Enable support for OpenGL Character Renderer

sent

savedconfig Without a saved config.h, this package depends on media-gfx/farbfeld for image conversions

spacefm

video-thumbnails Support video thumbnails with media-video/ffmpegthumbnailer

stalonetray

graceful-exit use non-portable hack to exit gracefully on signal

tint2

battery Enable battery status plugin
sanitize Enable ASAN
tint2conf Build/Install tint2conf as well

urxvt-perls

deprecated Install scripts which have been marked as deprecated by upstream

wbar

gtk Enables the gtk-based wbar-config GUI

x11vnc

xdamage Enable support for the Xdamage library
xfixes Enable support for the Xfixes library
xrandr Enable support for the X xrandr extension

xkbd

evdev Enable dev-libs/libevdev support for xtg
xi Enable XInput2 support through x11-libs/libXi
xrandr Enable XRandR support through x11-libs/libXrandr

xkbset

tk Install the dev-perl/Tk based xkbset-gui utility

xlockmore

vtlock Enables support for virtual terminal locking
xlockrc Enables xlockrc for people without PAM

xmobar

alsa Use alsa-mixer to get the volume from soundcards.
datezone Enables localized date support.
dbus Publish a service on the session bus for controlling xmobar.
mpd MPD support. Needs libmpd installed.
mpris MPRIS v1, v2 support.
rtsopts Use -with-rtsopts=-V0 to reduce wakeups.
timezone Enables localized date support.
uvmeter UVMeter only useful to australians.
weather Enable weather plugin.
wifi Wireless info support via nl80211. Required for the Wireless plugin on systems running Linux, the kernel.
xft Use Xft to render text. UTF-8 support included.
xpm Enable usage of xpm for icons.
xrender Use XRender for alpha background pseudo-transparency.

xscreensaver

fonts Install the fonts shipped with XScreenSaver that have clear licensing
gdk-pixbuf Include support for the x11-libs/gdk-pixbuf library in some demos, which will make it possible for them to read GIF, JPEG, and PNG files as well
gdm Use gdmflexiserver from gnome-base/gdm instead of x11-misc/lightdm
gles Emulate OpenGL 1.3 in terms of OpenGL ES 1.x
glx Use GLX to interface OpenGL and X11 instead of EGL
locking Compile in support for locking the display
logind-idle-hint Send the session idle hint to logind once the screen saver blanks
new-login Enable user switching support using gdmflexiserver (x11-misc/lightdm)

xsr

cursor Capture mouse cursor using x11-misc/xdotool, and place them on the screenshots using media-gfx/imagemagick

yabar

playerctl Uses media-sound/playerctl to retrieve the name of the currently played song

x11-plugins

bfm

gkrellm Enable building of app-admin/gkrellmmodule

e16-epplets

cdaudio Enable CD Audio support using media-libs/libcdaudio
libgtop Use gnome-base/libgtop to obtain system load information

pidgin-mbpurple

twitgin Enable graphical plugin for Gtk+ interface of Pidgin.

pidgin-sipe

ocs2005-message-hack Disable message timeout for OCS2005 clients which causes "false" not delivered error messages
openssl Enable crypto support via dev-libs/openssl
telepathy Support use as a telepathy backend
voice Enable experimental voice/video support

vicious

contrib Install extra widgets, some for less common hardware, some contributed by Vicious users.

wmbattery

apm Add APM (Advanced Power Management) support

wmfire

session Enable session management

wmudmount

gcr Enable support for secure memory with app-crypt/gcr

x11-terms

aterm

background Enable background image support via media-libs/libafterimage
xgetdefault Enable resources via X instead of aterm small version

gnome-terminal

gnome-shell Integrate with gnome-base/gnome-shell search
nautilus Build gnome-base/nautilus extension

guake

utempter Include utmp management support via sys-libs/libutempter

mlterm

brltty Enable support for app-accessibility/brltty
fcitx Enable support for app-i18n/fcitx
harfbuzz Enable support for OpenType Layout (media-libs/harfbuzz)
ibus Enable support for app-i18n/ibus
libssh2 Enable support for net-libs/libssh2
regis Enable support for ReGIS
scim Enable support for app-i18n/scim
skk Enable support for SKK (virtual/skkserv or app-i18n/skk-jisyo)
uim Enable support for app-i18n/uim
utempter Enable support for sys-libs/libutempter
wayland Enable support for Wayland

rxvt-unicode

24-bit-color Enable 24-bit color support. Note that this feature is unofficial, may cause visual glitches due to the fact there is no termcap/terminfo definition for rxvt-unicode-24bit yet so it is necessary to use the one for 256 colours, visibly increases memory usage, and might slow urxvt down dramatically when more than six fonts are in use in a terminal instance.
256-color Enable 256 color support
blink Enable blinking text
fading-colors Enable colors fading when off focus
font-styles Enable support for bold and italic fonts
gdk-pixbuf Enable transparency support using x11-libs/gdk-pixbuf
iso14755 Enable ISO-14755 support
mousewheel Enable scrolling via mouse wheel or buttons 4 and 5
perl Enable perl script support. You can still disable this at runtime with -pe ""
unicode3 Use 21 instead of 16 bits to represent unicode characters
wide-glyphs Enable support for wide glyphs, required for certain symbol/icon fonts to display correctly. Note that this feature is *unofficial* and has been observed to cause stability issues for some users.

terminology

extras Install additional testing tools

xfce4-terminal

utempter Include utmp management support via sys-libs/libutempter

xterm

openpty Use openpty() in preference to posix_openpt()
sixel Enable sixel graphics support
toolbar Enable the xterm toolbar to be built

x11-themes

QGnomePlatform

minimal Skip kde-frameworks/qqc2-desktop-style dependency (Warning: some apps could be wrongly rendered)

arc-theme

cinnamon Install theme for gnome-extra/cinnamon
gnome-shell Install theme for gnome-base/gnome-shell
gtk2 Install GTK+2 theme
gtk3 Install GTK+3 theme
gtk4 Install GTK+4 theme
mate Install Metacity theme for mate-base/mate
pre-rendered Avoid media-gfx/inkscape and media-gfx/optipng dependencies by using pre-rendered PNGs
transparency Enable transparency
xfce Install theme for xfce-base/xfwm4

comix-xcursors

lefthanded Install lefthanded version of theme in addition to default one.
opaque Install non-transparent version of theme in addition to default one.

fluent-icon-theme

black Install the black version of symbolic icons (for white color-scheme panels)
hardlink Hardlink duplicate icons to greatly reduce installation size
round Install the round version of symbolic icons

gentoo-artwork

grub Install extra sys-boot/grub themes
icons Install icons
lilo Install extra sys-boot/lilo themes
pixmaps Install pixmaps

gtk-engines-murrine

animation-rtl Progressbar animation from right to left
themes Pull in themes via x11-themes/murrine-themes

kfaenza

additional Install additional KFaenza icons. See third homepage for details

tela-icon-theme

black Install black folder version
blue Install blue folder version
brown Install bworn folder version
dracula Install dracula folder version
green Install green folder version
grey Install grey folder version
hardlink Hardlink duplicate icons to greatly reduce installation size
kde Install dynamic color version for KDE plasma (folder color follows the colorscheme)
manjaro Install manjaro folder version
nord Install nord folder version
orange Install orange folder version
pink Install pink folder version
purple Install purple folder version
red Install red older version
standard Install standard folder version
ubuntu Install ubuntu folder version
yellow Install yellow folder version

vertex-theme

cinnamon Install theme for gnome-extra/cinnamon
gnome-shell Install theme for gnome-base/gnome-shell
mate Install Metacity theme for mate-base/mate
xfce Install theme for xfce-base/xfwm4

zuki-themes

gnome-shell Install theme for gnome-base/gnome-shell
gtk2 Install GTK+2 theme
xfce Install theme for xfce-base/xfwm4

x11-wm

ctwm

jpeg Enable jpeg image support with virtual/jpeg
test Enable upstream test suite, build required binary
xpm Enable xpm icon support with x11-libs/libXpm

e16

debug Build libtrip debugging library
dialogs Enable support for configuration dialogs
libhack Build libhack window mode helper library
modules Enable support for loadable modules
no-container Do not use container window (experimental)
pango Enable pango font rendering using x11-libs/pango
player Enable audio using aplay from media-sound/alsa-utils
poll Use poll() event handler API (recommended)
select Use select() event handler API
themes Install the official E16 themes using x11-themes/e16-themes
xi2 Enable the experimental multipointer input XInput2. This incldues the MultiPointer X feature
xpresent Enable support for the X Present extension via x11-libs/libXpresent (experimental)
xrandr Enable support for the X RandR extension via x11-libs/libXrandr
xrender Enable transparency support using the X Render extension via x11-libs/libXrender
xsm Enable X Session Management support using x11-libs/libSM
xsync Enable X Sync support
zoom Support resolution change of current window (zoom) usingx11-libs/libXxf86vm (xvidtune)

echinus

xrandr Enable support for multihead configuration

enlightenment

xwayland Enable XWayland application support

fluxbox

slit Enables the Fluxbox slit (or dock)
systray Enables the system tray in the Fluxbox toolbar
toolbar Enables the Fluxbox toolbar

fvwm

lock Enable screen locking
netpbm Enable NetPBM support (used by FvwmScript-ScreenDump)
stroke Mouse Gesture support

fvwm3

go Enable building dev-lang/go code (FvwmPrompt)
lock Enable screen locking
netpbm Enable NetPBM support (used by FvwmScript-ScreenDump)
stroke Mouse Gesture support

i3

doc Build and install the HTML documentation and regenerate the man pages

icewm

gdk-pixbuf Enable gdk-pixbuf rendering

jwm

pango Bidirectional text layout support with pango using xft backend.

lumina

desktop-utils Build and install lumina's desktop-utils

metacity

libcanberra Enable sound event support using media-libs/libcanberra
vulkan Enable Vulkan based compositor support via META_COMPOSITOR=vulkan environment variable

muffin

sysprof Enable profiling data capture support using dev-util/sysprof-capture

musca

apis Optionally install the experimental `apis' window manager
xlisten Optionally install the xlisten utility

mutter

elogind Rely on sys-auth/elogind as logind provider for Wayland sessions
sysprof Enable profiling data capture support using dev-util/sysprof-capture

notion

xrandr Add support for xrandr

openbox

session Enables support for session managers
xdg Install the python xdg files for xdg autostart

pekwm

contrib Install optional extras in the documentation directory
pango Pango font support
themes Install additional themes

ratpoison

history Use sys-libs/readline for history handling
sloppy Install sloppy, a focus-follows-mouse implementation for ratpoison
xrandr Enable support for XRandR

stumpwm

doc Include documentation

windowmaker

modelock Enable XKB language status lock support. README says: "If you don't know what it is you probably don't need it."
xrandr Enable XRandR window extension support

wmfs

imlib2 Enable image support through media-libs/imlib2

xmonad

no-autorepeat-keys Allow ignoring of keyboard autorepeat.

xmonad-contrib

xft Use Xft to render text

xpra

client Build client-side code
clipboard Enable clipboard support
csc Enable csc softscaler support
html Install the HTML5 client
ibus Use ibus input method via app-i18n/ibus
oauth Enable OAuth2 authentication in the server
pinentry Use app-crypt/pinentry for password entry
server Build server-side code
trayicon Enable system tray icon
vpx Enable vpx image format support
webcam Enable webcam support via opencv
xdg Enable support for XDG-based menus

xfce-base

libxfce4ui

glade Build support for Glade 3's GtkBuilder implementation
system-info Enable system information in xfce4-about.

thunar

trash-panel-plugin Build the trash status indicator plugin for the XFCE panel

tumbler

epub Enable support for .epub thumbnailer using app-text/libgepub
odf Enable support for .odf thumbnailers by using gnome-extra/libgsf

xfce4-panel

dbusmenu Enable dev-libs/libdbusmenu integration (in status notifier plugin)

xfce4-power-manager

panel-plugin Build the power management plugin for the XFCE panel

xfce4-settings

libcanberra Enable sound event support using media-libs/libcanberra
xklavier Enable keyboard layout selection support using x11-libs/libxklavier

xfdesktop

thunar Build support for desktop icons (for example, launchers and folders)

xfwm4

xpresent Enable the XPresent extension for sync to vblank

xfce-extra

xfce4-clipman-plugin

qrcode Enable support for media-gfx/qrencode

xfce4-mixer

keybinder Enable support for global hotkeys using dev-libs/keybinder.
sndio Enable media-sound/sndio backend.

xfce4-pulseaudio-plugin

keybinder Enable support for global hotkeys using dev-libs/keybinder.
libcanberra Enable sound event support using media-libs/libcanberra
libxfce4windowing Enable experimental support for raising media player windows using xfce-base/libxfce4windowing.
wnck Enable experimental support for raising media player windows using x11-libs/libwnck.

xfce4-screensaver

locking Enable screen locking support

xfce4-whiskermenu-plugin

accountsservice Enable support for AccountsService.