gl_common: properly reject old OpenGL versions

The extension checking logic was broken, which reported OpenGL 3 if the
OpenGL .so exported OpenGL 3-only symbols, even if the reported OpenGL
version is below 3.0. Fix it and simplify the code a bit. Also never
fail hard if required functions are not found. The caller should check
the capability flags instead. Give up on the idea that we should print
a warning if essential functions are not found (makes loading of ancient
legacy-only extensions easier).

This was experienced with the following version strings:

OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) 915GM x86/MMX/SSE2
OpenGL version string: 1.4 Mesa 9.0.1

(Possibly reports a very old version because it has no GLSL support,
and thus isn't even GL 2.0 compliant.)

0 files changed, 0 insertions, 0 deletions