emulators/wine: Add ffmpeg support with winemdo

This (mostly) backports commit 22ee425d from emulators/wine-devel.

It fixes issues where cutscene will just hang indefinitely when using
gstreamer.

Once build with ffmpeg, it can be activated by setting the DWORD value
  DisableGstByteStreamHandler = 1
in the HKCU\Software\Wine\MediaFoundation registry key.

The default is to use gstreamer, so if the user does not change the
registry key, this should not change much.

PR:		290842