[Xcb] mesa +xcb = assertion death

[Jeremy Kolb]

Here's a backtrace of glxinfo btw:


#0  0xffffe410 in ?? ()
#1  0xbffff2ec in ?? ()
#2  0x00000006 in ?? ()
#3  0x00000c55 in ?? ()
#4  0xb7cb8931 in raise () from /lib/libc.so.6
#5  0xb7cba1dd in abort () from /lib/libc.so.6
#6  0xb7cb1e42 in __assert_fail () from /lib/libc.so.6
#7  0xb7e4010f in _XGetXCBBuffer (dpy=0x804d008) at xcl/xcblock.c:127
#8  0xb7e40198 in _XGetXCBBufferIf (dpy=0x6, locked=_XBufferUnlocked)
     at xcl/xcblock.c:165
#9  0xb7e401db in _XLockDisplay (dpy=0x804d008) at xcl/xcblock.c:18
#10 0xb7e41525 in _XReply (dpy=0x804d008, rep=0x0, extra=0, discard=0)
     at xcl/io.c:284
#11 0xb7f3b931 in AllocAndFetchScreenConfigs (dpy=0x804d008, priv=0x804fdf0)
     at glxext.c:1069
#12 0xb7f3bde9 in __glXInitialize (dpy=0x804d008) at glxext.c:1278
#13 0xb7f36f15 in GetGLXPrivScreenConfig (dpy=0x804d008, scrn=0,
     ppriv=0xbffff6a8, ppsc=0x0) at glxcmds.c:256
#14 0xb7f38851 in glXChooseVisual (dpy=0x804d008, screen=0, attribList=0x0)
     at glxcmds.c:1325
#15 0x08048fcc in main ()

Jeremy