https://bugs.freedesktop.org/show_bug.cgi?id=54341
--- Comment #1 from Marco mpiazza@gmail.com 2012-09-01 21:45:41 UTC --- Sorry, my mistake!
I wrote something wrong in the .drirc file leading to the crash. Removing .drirc makes glxgears (and all othe GL applications) start fine.
Sorry for the noise.