Global USE flags

Flag	Description	Packages
test		3

Local USE flags

app-portage

shengloong

Flag	Description
nls

dev-lang

ghc

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

sys-kernel

genkernel

Flag	Description
firmware	Prefer system firmware <pkg>sys-kernel/linux-firmware</pkg> over local copy.
ibm

www-client

chromium

Flag	Description
X
bindist
cups
debug	Enable DCHECK feature with severity configurable at runtime. Mostly intended for debugging and development, NOT RECOMMENDED for general use.
ffmpeg-chromium	(binpkg only) Use Chromium FFmpeg fork (<pkg>media-video/ffmpeg-chromium</pkg>) rather than mainline FFmpeg (<pkg>media-video/ffmpeg</pkg>)
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.
kerberos
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.
pulseaudio
qt5
qt6
screencast
selinux
system-harfbuzz	Use system <pkg>media-libs/harfbuzz</pkg> instead of the bundled library.
system-icu	Use system <pkg>dev-libs/icu</pkg> instead of the bundled one
system-png	Use system <pkg>media-libs/libpng</pkg> instead of the bundled library
system-toolchain	Use system toolchain instead of the bundled one (if possible)
system-zstd	Use system <pkg>app-arch/zstd</pkg> instead of the bundled one.
vaapi
wayland
widevine	Unsupported closed-source DRM capability (required by Netflix VOD)

x11-libs

pixman

Flag	Description
cpu_flags_arm_neon
cpu_flags_ppc_altivec
cpu_flags_x86_mmxext
cpu_flags_x86_sse2
cpu_flags_x86_ssse3
loongson2f	Enable Loongson2f MMI optimizations.
static-libs

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