Merge commit 'ebc29519d1'

* commit 'ebc29519d1':
  hwaccel: Support specific frame allocators

Conflicts:
	libavcodec/utils.c

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

libavcodec/avcodec.h

@@ -3242,6 +3242,11 @@ typedef struct AVHWAccel {
      */
     struct AVHWAccel *next;
 
+    /**
+     * Allocate a custom buffer
+     */
+    int (*alloc_frame)(AVCodecContext *avctx, AVFrame *frame);
+
     /**
      * Called at the beginning of each frame or field picture.
      *