github: Switch use of the msys2 mingw64 environment to ucrt64
github: Update to building and testing ffmpeg 9.0.2 instead of 6.1.2
github: Switch test-ffmpeg over to the msys2 environment ucrt64
github: Disable building docs in the ffmpeg builds
github: Update msys2 when setting up for test-ffmpeg
Fix building i686 with GCC (without SSE globally enabled)
Bump the version numbers for fdk-aac 3.0.0
check-install: Check the MachO current/compatibility version too