Feature Request: also build libplacebo

[CounterPillow]

With mpv more and more depending on libplacebo, it makes sense that people would be able to use mpv-build to try out bleeding-edge mpv features (gpu-next) that depend on a bleeding-edge version of libplacebo. So I'd like to request that much like ffmpeg and libass, libplacebo is built in the same fashion, with a switch between the git version and the release version.

[Dudemanguy]

Could be pretty trivially done with meson wraps (of course, that would be meson-specific but still).