FWIW, I have determined that WoW now requires OpenGL >= 3.2 when running in
OpenGL mode, and I suspect that the function call that kills WoW when running
with OpenGL < 3.2 is glDeleteSync().

Now it seems that glDeleteSync() belong to the ARB_sync extension, which Mesa
*does* advertise as part of my OpenGL 3.0 Compatibily context, so I can't say
that I completely understand what is going on here. Could there be a Mesa bug
after all, or is it more likely that the WoW client is just being sloppy?