Originally mpv vaapi support was based on the MPlayer-vaapi patches.
These were never merged in upstream MPlayer. The license headers
indicated they were GPL-only. Although the actual author agreed to
relicensing, the company employing him to write this code did not, so
the original code is unusable to us.
Fortunately, vaapi support was refactored and rewritten several times,
meaning little code is actually left. The previous commits removed or
moved that to GPL-only code. Namely, vo_vaapi.c remains GPL-only. The
other code went away or became unnecessary mainly because libavcodec
itself gained the ability to manage the hw decoder, and libavutil
provides code to manage vaapi surfaces. We also changed to mainly using
EGL interop, making any of the old rendering code unnecessary.
hwdec_vaglx.c is still GPL. It's possibly relicensable, because much of
it was changed, but I'm not too sure and further investigation would be
required. Also, this has been disabled by default for a while now, so
bothering with this is a waste of time. This commit simply disables it
at compile time as well in LGPL mode.