Unix socket creation returns EADDRINUSE for all other errors. Looks like it's a simple merge problem from annotating upstream. This causes problems starting rhgb the second time you boot (when /tmp/.X11-unix) already exists as the bind gets EROFS but treats it as EADDRINUSE.
Created attachment 98768 [details] the fix Also, filed upstream as http://freedesktop.org/cgi-bin/bugzilla/show_bug.cgi?id=363
Patch added to xorg-x11-0.0.6.6-0.0.2004_03_11.7 which is now present in dist-fc2. Closing as 'RAWHIDE'