Original commit message from CVS:
Simplify alsa checking: we can use the standard AM_PATH_ALSA macro to
check that we don't have alsa 0.9.x: we just need to specify something
for ACTION_NOT_FOUND to override the default AC_MSG_ERROR behaviour, so
I've put a colon for ACTION_NOT_FOUND. ;-)
Also, update the alsa macro in acinclude with the latest from the alsa
project CVS.