[PATCH v6 0/3] MR9704: winmm, msvfw32: DGV window shenanigans with audio only files

[Bernhard Kölbl (＠besentv)]

Basically, check if we can set a HWND in the driver, before doing so.
Right now, msvfw32 + mciqtz32 error out on audio only playbacks, breaking the game Transcendence.

--
  v6: msvfw32: Only attempt to set a digital-video window, when the driver has a window itself.
      msvfw32/tests: Add a basic audio playback test.
      winmm/tests: Test digital-video window behavior for audio files.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/9704