Comment 4 for bug 149260

Sadly, the problem reappeared when I updated to the official
beta version (2.1.1-0ubuntu6). I just checked the Debian bug
report again, and I see the fix was a change to the Mesa
package. Gutsy's Mesa package does seem to have the fix:

+ * Build with -fno-strict-aliasing to fix misbuild of i965_dri.so
+ (closes: #394311). Thanks to Michel Dänzer for the fix, and to Ryan
+ Richter for the report and testing.

cf. http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=394311

but maybe we missed something. The package you linked
to directly -- was it compiled differently, perhaps in a way that
turned off the -fstrict-aliasing optimization?