bad m4 syntax with automake 1.8.x
people who have automake 1.8.x would see warnings like :
/usr/share/aclocal/vorbis.m4:9: warning: underquoted definition of XIPH_PATH_VORBIS
when running any ./autogen.sh
AC_DEFUN(XIPH_PATH_VORBIS,
should be
AC_DEFUN([XIPH_PATH_VORBIS],
then, automake would be silent