gen ~ # emerge -vp gtk+:2  gtk+:3
[ebuild   R   ] x11-libs/gtk+-3.20.9  USE="X cups introspection xinerama* (-aqua) -broadway -cloudprint -colord -examples {-test} -vim-syntax -wayland" ABI_X86="32 (64) (-x32)"
[ebuild   R   ] x11-libs/gtk+-2.24.31  USE="cups introspection xinerama* (-aqua) -debug -examples {-test} -vim-syntax" ABI_X86="32 (64) (-x32)"