Bug#394716: TNL context is NULL

[Alexander E. Patrakov]

The original submitter has the GLcore module loaded unconditionally in 
his xorg.conf file. What happens is:

1) Xorg loads the GLcore module that has some tnl-related symbols
2) Xorg loads the r200_dri library for AIGLX, and this library also 
contains the same tnl-related symbols
3) the dri module unexpectedly uses symbols from GLcore.

The fix is to comment out the Load "GLcore" line from xorg.conf, and to 
add Option "AIGLX" to the ServerLayout section.

So, while this bug report is a result of local misconfiguration, I do 
not close it now, because xorg can behave better. It should warn about 
symbol conflicts between modules and refuse loading DRI modules for 
AIGLX if GLcore is already loaded.

-- 
Alexander E. Patrakov