you might like to try fmod (http://fmod.org).
In the documentation for fmod_ex it only shows the c++ interface, but the c interface is alsmot exactly the same (Fmod::CreateStream becomes Fmod_CreateStream or something, just look at the C files in the examples folder).
Fmod_ex lets you use one single interface to play ogg files, mp3 files, wav files (PCM or ADPCM or AIFF and maybe some others, GSM perhaps im not sure), s3m files, mod, xm, it files, and flac files (or decoded from memory, good for datafiles) and you can even give a url to them and they will be streamed off the net. I like it becuase it's really simple and hassle-free and is still cross-platform compatible.
The only issue i have with it is it, unlike DUMB, doesn't honor the Zxx comands in .it files (so a few cool effects are completely ignored). I've never once used any allegro sound things (i looked at them once, and decided to keep on searching, once i found fmod i never really turned back).
Oh yeah, as far as i know fmod places no external dependencies except for it's runtime dl library/object. You just download it, and copy the sources into your include dir and the mingw libfmod.a into your lib folder (or on linux type make install as root and it's finsihed). It's insanely easy.
Some of the examples failed to build on my linux box, but i didn't care, it still works great, and i later built them by hand and all worked properly.