Contrary to what’s intended, SDL_mixer ends up not linking against libmikmod. Its ./configure run goes like this:
--8<---------------cut here---------------start------------->8--- checking for fork... yes checking for vfork... yes checking for libmikmod-config... /gnu/store/32mqj92g8bmq8bmr84sw2gckifld0ga0-libmikmod-3.3.3/bin/libmikmod-config checking for libmikmod - version >= 3.1.10... configure: WARNING: *** Unable to find MikMod library (http://mikmod.raphnet.net/) configure: WARNING: MOD support disabled --8<---------------cut here---------------end--------------->8--- So it’s failing somewhere after the AC_PATH_PROG for libmikmod-config. Ludo’.