Ensure av_tree_insert() is defined before using it.

Patch by Carl Eugen Hoyos   cehoyos _at_ ag.or.at


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@10083 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavformat/nut.c

@@ -20,6 +20,7 @@
  */
 
 #include "nut.h"
+#include "tree.h"
 
 unsigned long av_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf, unsigned int len){
     return av_crc(av_crc04C11DB7, checksum, buf, len);