Bring back auto-detection of PulseAudio

Bring back auto-detection of PulseAudio

	* configure.ac (with-sound): Re-enable PulseAudio.

	* configure.ac (with-pulseaudio): Removed.  It is now back in
	with-sound.

	* configure.ac: Nuke the `pulse_*_version' vars.  They weren't
	being used for anything.

	* src/media/Makefile.am (libmm_a_CFLAGS): Add MM_CFLAGS.

	* src/media/sound-pulse.c (stream_write_callback): Set
	`resolution', `real_frm_sz', and `ctx' as unused. Shush compiler.

Signed-off-by: Steve Youngs <steve@sxemacs.org>