DYN_SNDFILE=NO and DYN_MPG123=NO were ignored while DYN_FLUIDSYNTH=NO broke compilation
These options should be applied to ZMusic target instead of the main executable
As a bonus, it's now possible to build GZDoom without FluidSynth
This was the last player class.
This code was also cleaned up for non-Windows systems where CD Audio is not implemented.
Instead of providing an empty implementation, all related code is now explicitly deactivated.