[x11-libs/xcb-util-image] add true multilib support, import from FireBurn overlay
[x11-libs/xcb-util-renderutil] add true mutlilib support, import from FireBurn
[x11-libs/xcb-util-wm] add true multilib support, import from FireBurn
[x11-libs/xcb-util-keysyms] add true multilib support, import from FireBurn