af_aresample: switch to child_class_iterate()

libavfilter/af_aresample.c

@@ -293,10 +293,19 @@ static int request_frame(AVFilterLink *outlink)
     return ret;
 }
 
+#if FF_API_CHILD_CLASS_NEXT
 static const AVClass *resample_child_class_next(const AVClass *prev)
 {
     return prev ? NULL : swr_get_class();
 }
+#endif
+
+static const AVClass *resample_child_class_iterate(void **iter)
+{
+    const AVClass *c = *iter ? NULL : swr_get_class();
+    *iter = (void*)(uintptr_t)c;
+    return c;
+}
 
 static void *resample_child_next(void *obj, void *prev)
 {
@@ -317,7 +326,10 @@ static const AVClass aresample_class = {
     .item_name        = av_default_item_name,
     .option           = options,
     .version          = LIBAVUTIL_VERSION_INT,
+#if FF_API_CHILD_CLASS_NEXT
     .child_class_next = resample_child_class_next,
+#endif
+    .child_class_iterate = resample_child_class_iterate,
     .child_next       = resample_child_next,
 };