http://bugs.winehq.org/show_bug.cgi?id=29982
--- Comment #9 from PeterKraus petkra@chem.gla.ac.uk 2012-03-25 10:14:32 CDT --- It looks like it's mesa. Recompiling 32bit mesa with -O1 (instead of O2) seems to fix the issue, as described here:
https://bugs.archlinux.org/task/27645