xorg HEAD + Mesa HEAD = boom

[Benjamin Herrenschmidt]

Haven't had time to investigate much yet (and probably won't for a
couple of weeks) but with a build of today's CVS Mesa, r300 DRI, and X
against that Mesa version (the whole lot), the server blows up right
away when launching glxinfo or glxgears.

The latest log I got (with glxgears) shows this backtrace:

Backtrace:
0: /usr/local/xorg/bin/X(xf86SigHandler+0xa4) [0x10082344]
1: [0x100374]
2: [0x10c5b548]
3: [0x10c5b548]
4: /usr/local/xorg/lib/xorg/modules/extensions/libGLcore.so(xmesa_resize_buffers+0x54) [0xf61c004]
5: /usr/local/xorg/lib/xorg/modules/extensions/libGLcore.so(XMesaResizeBuffers+0x60) [0xf61ac54]
6: /usr/local/xorg/lib/xorg/modules/extensions/libGLcore.so [0xf616f04]
7: /usr/local/xorg/lib/xorg/modules/extensions/libglx.so(DoMakeCurrent+0x5d8) [0xf98e06c]
8: /usr/local/xorg/lib/xorg/modules/extensions/libglx.so(__glXMakeCurrent+0x24) [0xf98e164]
9: /usr/local/xorg/lib/xorg/modules/extensions/libglx.so [0xf993d94]
10: /usr/local/xorg/bin/X(Dispatch+0x21c) [0x10043c40]
11: /usr/local/xorg/bin/X(main+0x47c) [0x10025170]
12: /lib/libc.so.6 [0xfc558ec]
13: /lib/libc.so.6 [0xfc55a34]