libao rpm doesn't build/work on distributions w/o alsa (i.e. redhat)
The file libao.spec included in the libao distribution contains a build-dependency on alsa-lib-devel, a package that is unavailable in several major distributions. This prevents the libao package from being built and used on for example redhat. The src and binary rpms on www.vorbis.com also needs to be updated once this is fixed.