Activate osxaudio in gst-plugins-good with proper build setup.

Activate osxaudio in gst-plugins-good with proper build setup.

Original commit message from CVS:
* configure.ac:
* sys/Makefile.am:
* sys/osxaudio/Makefile.am:
* sys/osxaudio/gstosxaudio.c:
* sys/osxaudio/gstosxaudiosink.c:
(gst_osx_audio_sink_osxelement_do_init), (gst_osx_audio_sink_init),
(gst_osx_audio_sink_getcaps),
(gst_osx_audio_sink_create_ringbuffer), (plugin_init):
* sys/osxaudio/gstosxaudiosrc.c:
(gst_osx_audio_src_osxelement_do_init), (gst_osx_audio_src_init),
(gst_osx_audio_src_create_ringbuffer):
* sys/osxaudio/gstosxringbuffer.c: (gst_osx_ring_buffer_get_type),
(gst_osx_ring_buffer_class_init), (gst_osx_ring_buffer_init),
(gst_osx_ring_buffer_acquire), (gst_osx_ring_buffer_start),
(gst_osx_ring_buffer_pause), (gst_osx_ring_buffer_stop):
* sys/osxaudio/gstosxringbuffer.h:
Activate osxaudio in gst-plugins-good with proper build setup.
Add inlined documentation.
Fix debug statements
Fix ringbuffer when pausing.
Fixes #323471