In the upstream hg (http://hg.libsdl.org/SDL_mixer/shortlog), there are a few patches, that combined finally bring libmodplug support (independent from libmikmod) to sdl-mixer. Consider adding those to the tree.
Created attachment 241415 [details, diff] full, cleaned up, patch It requires 'AT_M4DIR="acinclude" eautoreconf'. configure option is '--enablemusic-mod-modplug'. I'd also consider hidden symbols patch.
typo: '--enable-music-mod-modplug'
we'll pick them up in the next release. cherry-picking from upstream is a maintenance nightmare.