cat /etc/portage/package.use/custom
# required by dev-qt/qt-creator-2.8.1
# required by dev-qt/qt-creator (argument)
=dev-libs/botan-1.10.3 threads
# required by dev-util/nvidia-cuda-toolkit-6.5.14
# required by dev-util/nvidia-cuda-sdk-6.5.14
# required by dev-util/nvidia-cuda-sdk (argument)
>=x11-drivers/nvidia-drivers-346.35 uvm
# required by x11-misc/bumblebee-3.2.1
# required by x11-misc/bumblebee (argument)
=x11-base/xorg-drivers-1.15 video_cards_nvidia
# required by dev-qt/qtgui-5.4.0[xcb]
# required by dev-qt/qtwidgets-5.4.0
# required by dev-qt/qtwidgets (argument)
=x11-libs/libxcb-1.10 xkb
# required by dev-qt/qtcore-5.4.0
# required by dev-qt/qtsensors-5.4.0
# required by dev-qt/qtsensors (argument)
=dev-libs/libpcre-8.35 pcre16
# required by sys-apps/systemd-216-r3
# required by gnome-base/gnome-control-center-3.12.1-r1
# required by gnome-base/gnome-shell-3.12.2
# required by gnome-base/gdm-3.12.2-r2
# =sys-apps/dbus-1.8.10 systemd
# required by gnome-base/gdm-3.12.2-r2
# required by gnome-base/gnome-shell-3.12.2
# required by gnome-base/gnome-shell (argument)
# =sys-auth/pambase-20120417-r3 systemd