If gtk is built with X11, gnome-terminal depends on libX11 as well: for target in $($PKG_CONFIG --variable targets gdk-$GTK_API_VERSION); do case "$target" in x11) PLATFORM_DEPS="$PLATFORM_DEPS x11" ;; pkg-config --variable targets gdk-3.0 x11 wayland
*** This bug has been marked as a duplicate of bug 624960 ***
Comment in gnome-terminal ebuild points to bug 624960 for gtk+[X] dep