sha: add missing include

Originally committed as revision 22449 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/sha.c

@@ -22,6 +22,7 @@
  */
 
 #include <string.h>
+#include "avutil.h"
 #include "bswap.h"
 #include "sha.h"
 #include "sha1.h"