Here is a patch for adding pkg-config support to libmad. It would make life a bit easier for distro maintainers if this was applied. In case you didn't know, pkg-config is a tool for providing LDFLAGS and CFLAGS for packages using shared libraries. It's on freedesktop.org. Debian has already been distributing the pkg-config file mad.pc with libmad for some time, and people developing on debian (notably xmms2 developers) have started relying on this support being present, causing some confusion for people installing from source and on some BSDs which do not provide mad.pc (google: pkgconfig libmad).