Move VLC and RL_VLC_ELEM structure definitions to a separate header

Use the newly created vlc.h directly instead of including get_bits when needed.
The VLC and RL_VLC_ELEM structures are independent from the bitreader.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

libavcodec/rl.c

@@ -17,6 +17,7 @@
  */
 
 #include <stdint.h>
+#include <string.h>
 
 #include "libavutil/attributes.h"
 #include "libavutil/mem.h"