Here is my /etc/portage/make.conf if it will help on the use variable.
I'm sending the whole file since it may have other errors.
# These settings were set by the catalyst build script that automatically
# built this stage.
# Please consult /usr/share/portage/config/make.conf.example for a more
# detailed example.
COMMON_FLAGS="-march=native -O2 -pipe"
CFLAGS="${COMMON_FLAGS}"
CXXFLAGS="${COMMON_FLAGS}"
FCFLAGS="${COMMON_FLAGS}"
FFLAGS="${COMMON_FLAGS}"
# NOTE: This stage was built with the bindist Use flag enabled
PORTDIR="/var/db/repos/gentoo"
DISTDIR="/var/cache/distfiles"
PKGDIR="/var/cache/binpkgs"
MAKEOPTS="-j2"
# This sets the language of build output to English.
# Please keep this setting intact when reporting bugs.
LC_MESSAGES=C
USE="mmx sse sse2 accessibility -qt3 -qt4 gtk3 nsplugin -kerberos flac ogg
-pulseaudio -consolekit systemd -libav -wayland"
ACCEPT_LICENSE="* -@EULA"
PHP_TARGETS="php7-4 php7-3"
EMERGE_DEFAULT_OPTS="--ask --color=n --verbose --nospinner --quiet-build=n
--backtrack=200"
ACCEPT_KEYWORDS="~x86 ~amd64"
VIDEO_CARDS="nouveau"
GENTOO_MIRRORS="http://gentoo.mirrors.easynews.com/linux/gentoo/
http://www.gtlib.gatech.edu/pub/gentoo rsync://rsync.gtlib.gatech.edu/gentoo
https://gentoo.osuosl.org/ http://gentoo.osuosl.org/
http://gentoo.mirrors.pair.com/ https://mirrors.rit.edu/gentoo/
http://mirrors.rit.edu/gentoo/ ftp://mirrors.rit.edu/gentoo/
rsync://mirrors.rit.edu/gentoo/ http://gentoo.mirrors.tds.net/gentoo
http://gentoo.cs.utah.edu/";
--
