Comment 7 for bug 1251281

Testing showed that disabling GL enforcement is not enough.
Seems like gnome-session-3.9.99 suffers from severe stability issues, it crashes frequently with GL enforcement disabled.
I've prepared back-ported from gnome 3.12 package:
https://launchpad.net/~eugenesan/+archive/ppa/+sourcepub/4095467/+listing-archive-extra
It contains a fix for GL enforcement (100_kill_gl_enforcement.patch) and upstream fixes, combined they solve the problem.

I hope package maintainers will find a way to "extract" the fix from the package above or import it to official repos.