У кого какой?
cat /etc/portage/make.conf
# my conf
CC="clang"
CXX="clang++"
COMMON_FLAGS="-march=native -mtune=native -O2 -pipe \
-fomit-frame-pointer -fno-stack-protector"
CFLAGS="${COMMON_FLAGS} -flto=thin"
CXXFLAGS="${COMMON_FLAGS} -flto=thin"
FCFLAGS="${COMMON_FLAGS}"
FFLAGS="${COMMON_FLAGS}"
AR="llvm-ar"
NM="llvm-nm"
RANLIB="llvm-ranlib"
FEATURES="-parallel-fetch nodoc noinfo -xattr -sandbox"
GENTOO_MIRRORS="http://gentoo-mirror.alexxy.name/ http://gentoo.bloodhost.ru/"
MAKEOPTS="-j2"
PORTDIR="/var/db/repos/gentoo"
DISTDIR="/var/cache/distfiles"
PKGDIR="/var/cache/binpkgs"
ALSA_CARDS="hda-intel"
LCD_DEVICES="ncurses text"
VIDEO_CARDS="intel iris i965"
APACHE2_MODULES=""
GPSD_PROTOCOLS=""
XTABLES_ADDONS=""
L10N="ru en"
CPU_FLAGS_X86="aes avx avx2 f16c fma3 mmx mmxext pclmul popcnt rdrand \
sse sse2 sse3 sse4_1 sse4_2 ssse3"
LC_MESSAGES=C
ACCEPT_LICENSE="*"
OFF="-acl -vala -fortran -ipv6 -nls -seccomp -tcpd -xattr -pam -pcre \
-ssp -perl"
ON="vaapi aac acpi alsa cairo dbus flac gif icu jpeg lcms libnotify mad \
mp3 mp4 mpeg opengl pango png svg tiff truetype upower udev x264 xml \
xv xvid X xcb"
USE="${ON} ${OFF}"