Merge commit '9d3009c6'

* commit '9d3009c6':
  avconv: print an error on applying options of the wrong type.
  atomic: Check for __sync_val_compare_and_swap instead of __sync_synchronize
  output-example: Update to use encode_video2 instead of the now dropped encode_video

Conflicts:
	doc/examples/muxing.c
	ffmpeg_opt.c
	libavutil/atomic.h

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