Remove ddio_CreateDir(), ddio_RemoveDir(), ddio_SaveWorkingDir(), ddio_RestoreWorkingDir(), ddio_DirExists(). Replace them in code with std::fs alternatives.
CD-ROM code needs specific hardware to be tested and maintained, and does not fit with the modernization this project envisions.
I doubt the Mac hardware we now target have built-in CDrom readers anymore.
To play using data from a CD-ROM, it needs to be mounted, and the mount address to be provided to the -setdir argument
