• Update mpv to 0.20.0
• Update waf to 1.9.3
• Remove patch demux: undefined behavior with ogg metadata update (fixed upstream)
• Record indirect dependencies.

Changelog:

https://github.com/mpv-player/mpv/releases/tag/v0.20.0

Reviewed by: feld (mentor)
Approved by: feld (mentor)
Differential Revision: D7672