Bug#257329: More info

[Dennis Brakhane <dennis@uni-hd.de>]

I managed to track the error down futher.

- SDL calls glXMakeCurrent, which returns True, but
- then SDL calls glGetString(GL_EXTENSIONS), which complains about 
"without a current context" and returns NULL

SDL assumes that this call succeeds, and does no futher checking before 
feeding it into strstr, leading to the segfault.

So, while the final reasoh for the crash is SDLs fault, I wonder why 
glGetString returns 0 and says it doesn't have a current Context, while 
at the same time letting glXCurrentContext succeed.

BTW: If I simply skip the strstr-check, the program runs perfectly, so 
the context IS working, or am I missing something here?