The alsa-xmms ebuild refuses to compile, stating that it cannot find a version of the alsa libs against which it can compile. A poke through the config.log reveals that it is trying to call snd_cards(), which is apparently no longer in libasound.so. It doesn't appear that the package has been updated in over two years. I recommend replacing it with this one, which compiled nicely and seems to be working just fine: http://savannah.gnu.org/projects/alsa-xmms
It seems alsa-xmms is updated to use the source from http://savannah.gnu.org/projects/alsa-xmms now.