Thanks Timothy.

Only this, since I did not build mesa in debug mode.
==8065== Conditional jump or move depends on uninitialised value(s)
==8065==    at 0xA986CE4: ??? (in /usr/lib64/mesa/r600g_dri.so)
==8065==    by 0xA988E14: ??? (in /usr/lib64/mesa/r600g_dri.so)
==8065==    by 0xA98A899: ??? (in /usr/lib64/mesa/r600g_dri.so)
==8065==    by 0xA96C910: ??? (in /usr/lib64/mesa/r600g_dri.so)
==8065==    by 0xA9766C2: ??? (in /usr/lib64/mesa/r600g_dri.so)
==8065==    by 0xA978FA6: ??? (in /usr/lib64/mesa/r600g_dri.so)
==8065==    by 0xA8CAD66: ??? (in /usr/lib64/mesa/r600g_dri.so)
==8065==    by 0xA7268CE: ??? (in /usr/lib64/mesa/r600g_dri.so)
==8065==    by 0xA6F6379: ??? (in /usr/lib64/mesa/r600g_dri.so)
==8065==    by 0x402701: main (mc.c:244)