Merge remote-tracking branch 'qatar/master'

* qatar/master:
  pthread: add some malloc failure checks
  avconv: cosmetics, reformat transcode_init()
  avconv: rename 'os' variable to 'oc'
  doc/filters: fix some typos.
  configure: add libpulse to help output

Conflicts:
	avconv.c
	configure

Merged-by: Michael Niedermayer <michaelni@gmx.at>