I don't know if your 1.14.4 version supports floating points already - last time I was aware of it was supported by last svn trunk "only".
So maybe pull from there and compile again.
Anyway, in the default sources is a "cheap hack" included to get your floating points enabled by force.
/* Simple hack to enable floating point output. */
if(argc >= 4 && !strcmp(argv[3], "f32")) mpg123_param(mh, MPG123_ADD_FLAGS, MPG123_FORCE_FLOAT, 0.);
As seen here: http://www.mpg123.de/api/mpg123_to_wav_8c_source.shtml