according to the mpg123 NEWS file mpg123_feed was introduced with 1.5.0 if this is actually the lowest version to compile with, it should be checked by ./configure if possible.
linking against system libmpg123 does have other issues however. im building a 32 bit wine on a 64 bit box here and i have installed a 32 bit libary of libmpg123 of course, however:
mpegl3.o: In function `MPEG3_Reset': mpegl3.c:(.text+0xca): undefined reference to `mpg123_feedseek'
the symbol is actually mpg123_feedseek_64 (which seems to be the case on a pure 32 bit box too according to one reporter) mpg123_findseek is correct for 64 bit however as there isn't mpg123_findseek_64 in my 64 bit libary.