configure.ac (DEFAULT_AUDIOSINK, DEFAULT_AUDIOSRC): Use alsa by default. Also because it's the only thing that really...

Original commit message from CVS:
2005-07-18  Andy Wingo  <wingo@pobox.com>

* configure.ac (DEFAULT_AUDIOSINK, DEFAULT_AUDIOSRC): Use alsa by
default. Also because it's the only thing that really works. (This
is used in the GConf elements).
Use AS_LIBTOOL_TAGS. Fix crap commit re: gettext.