Description of problem: xcb-util-0.3.6 requires libxcb-1.4, we have libxcb-1.3 in Rawhide. http://xcb.freedesktop.org/dist/
Fixed in rawhide.
Looks like libxcb-1.4 failed to build in Koji due to other deps problem.
Argh. Rebuilt, fixed for real now.