if you don't have scripts for those I can put up a patch file (they were really trivial to make.)
Well, the development of the SFML 1.x branch is officially stopped (except for bug fixes), so I'm never going to change the build system here.
Depending on what libraries are available
What does that mean? If it relies on other external shared libraries, I don't see any reason to replace libsndfile with it.
it covers the most common ones that most games actually need
Yep, this is fine for me. Too bad there's no MIDI or MP3 (maybe for the same reasons as me).
As for maintenance, Allegro 5 seems to be in healthy development.
Won't it be tedious to synchronize your own clone everytime there's an update?