0.41.0-av4

Combined MPVKit.xcframework (GPL) for iOS/tvOS.

• vo_avfoundation video output (PiP, composite OSD, VideoToolbox, HDR/DV)
• ao_audiounit clamps hardware channel layouts it cannot map to mp
  speaker IDs, instead of building an invalid chmap and playing
  silence. Fixes HDMI routes that report 32 discrete channels with
  Atmos "Continuous Audio Output".
• avfoundation audio output is still built but should NOT be used on
  tvOS: its clock carries no device-latency term, which stutters
  video over HDMI. audiounit is the default and the right choice.
• mpv v0.41.0, FFmpeg n8.1