Merge commit 'c7e921a5'

* commit 'c7e921a5':
  avopt: Check whether the object actually has got an AVClass

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

libavutil/opt.c

@@ -1294,6 +1294,9 @@ const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,
 
     c= *(AVClass**)obj;
 
+    if (!c)
+        return NULL;
+
     if (search_flags & AV_OPT_SEARCH_CHILDREN) {
         if (search_flags & AV_OPT_SEARCH_FAKE_OBJ) {
             const AVClass *child = NULL;