OK abieber@
Upstream changelog:
Quake II 5.34 to 6.00:
- Make the client asynchronous. The old behaviour can be forced by
setting cl_async to 0. Please note that asynchronicity can lead to
problems if the old SDL 1.2 backend is used and vsync is enabled.
- Implement gl_overbrightbits in the non multitexturing case. A value
of 1 just fixes lighting on water surfaces, higher values increase
the brightness of everything.
- General renderer overhaul for better compatibility with modern GPUs.
OpenGL 1.4 is now required, older versions are no longer supported.
Multitexturing was deprecated and will be removed in a future release.
- Fix some longstanding AI problems.
- Several general gameplay fixes.
cd4a2943eb