mpv-player/mpv — pull request #454 by Nikoli (2014-01-04 17:50:55+00:00)
Title: build: make opengl-old video output optional

All my systems have new enough mesa: opengl VO works fine with both r600 and nouveau drivers. So i would like to disable opengl-old VO at build time.
```
# time USE='opengl-old' MAKEOPTS="-j1" emerge -1vb --nodeps mpv;du -s /usr/bin/mpv
'build' finished successfully (4m25.780s)
real 6m15.809s
user 5m44.179s
sys 0m40.105s
1345 /usr/bin/mpv

# time USE='-opengl-old' MAKEOPTS="-j1" emerge -1vb --nodeps mpv;du -s /usr/bin/mpv
'build' finished successfully (4m15.652s)
real 6m4.894s
user 5m34.077s
sys 0m39.904s
1308 /usr/bin/mpv
```