lavfi: deprecate avfilter_link_set_closed().

Applications are not supposed to mess with links,
they should close the sinks.
Furthermore, this function does not distinguish what end
of the link caused the close and does not have a timestamp.

doc/APIchanges

@@ -14,6 +14,12 @@ libavutil:     2015-08-28
 
 
 API changes, most recent first:
+
+2015-12-22 - xxxxxxx - lavfi 6.21.101 - avfilter.h
+  Deprecate avfilter_link_set_closed().
+  Applications are not supposed to mess with links,
+  they should close the sinks.
+
 2015-12-17 - lavc 57.18.100 / 57.11.0 - avcodec.h dirac.h
   xxxxxxx - Add av_packet_add_side_data().
   xxxxxxx - Add AVCodecContext.coded_side_data.

libavfilter/avfilter.h

@@ -546,7 +546,10 @@ int avfilter_link_get_channels(AVFilterLink *link);
 
 /**
  * Set the closed field of a link.
+ * @deprecated applications are not supposed to mess with links, they should
+ * close the sinks.
  */
+attribute_deprecated
 void avfilter_link_set_closed(AVFilterLink *link, int closed);
 
 /**

libavfilter/version.h

@@ -31,7 +31,7 @@
 
 #define LIBAVFILTER_VERSION_MAJOR   6
 #define LIBAVFILTER_VERSION_MINOR  21
-#define LIBAVFILTER_VERSION_MICRO 100
+#define LIBAVFILTER_VERSION_MICRO 101
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \