No idea if this compiles yet (let alone if what is there works at all), just getting this out the way so I can work on certain other things *cough plane displacement cough*
Use whatever names you want for your music. So long as you prefix the lumps with O_ or D_, it doesn't matter anymore.
DISCLAIMER: Linedef type 413 (change music) and Lua scripting is not tested.
(cherry picked from commit 025ca413a2)
# Conflicts:
# src/p_user.c