Currently all it contains are the MIDI sources and the MIDI devices, the rest needs to be reworked first.
# Conflicts:
# libraries/zmusic/i_module.cpp
# libraries/zmusic/i_module.h
# src/CMakeLists.txt
# src/i_module.cpp
# src/i_module.h
# src/sound/music/midi_cvars.cpp
# src/utility/i_module.cpp
# src/utility/i_module.h
# Conflicts:
# src/CMakeLists.txt
# src/sound/musicformats/music_opl.cpp
This isn't the final location but this means that the device is merely a data provider, with the sole exception of the Win32 MIDI device whose unwieldy usage requirements unfortunately dictate much of the needed interface here.