Andrew, I "believe" I have the whole heap checked into GIT.  Please verify at your convenience (as long as it is before the morning of the 31st !! smiley face).  I played a few different audio tracks.  This last GIT checkin included:

0002-Fix-build-in-pluginfclient.C-with-ffmpeg-6.0.patch
0008-Possible-fix-internal-ffmpeg-5.1-build-with-binutils.patch

My understanding is that  ffmpeg-5.1.patch999 is already part of ffmpeg-6.0 so does not have to be carried -- I looked at the 6.0 mathops.h and it appears to be there.  If I am wrong, please let me know.