Remove libaudiofile and libmad as FFmpeg handles these formats and a lot more
FLAC can also be removed if FLAC encoding is deemed unnecessary.
FFmpeg handles some of the formats libsndfile supports however not the following:
iff", "svx", /* Commodore Amiga IFF / SVX */
"w64", /* Soundforge */
"xi", /* Fasttracker */
"htk", /* HMM Tool Kit */
"sd2", /* Sound Designer II */