Merge commit '2240e92f'

* commit '2240e92f':
  atomic: Add include guards to the implementation headers
  lavc: update the fallback versions of ff_thread_*

Conflicts:
	libavcodec/utils.c
Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/utils.c

@@ -2991,7 +2991,6 @@ int ff_thread_ref_frame(ThreadFrame *dst, ThreadFrame *src)
 int ff_thread_get_buffer(AVCodecContext *avctx, ThreadFrame *f, int flags)
 {
     f->owner = avctx;
-
     return ff_get_buffer(avctx, f->f, flags);
 }