Mac OS only gained pthread_setname_np in 10.6...
Mac OS only gained pthread_setname_np in 10.6...

...and our build servers apparently run 10.5!

Change-Id: I69c2f2212e616d83c043bb24e683b5437bceea54

treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst