Make libavfilter define its version like the other libav* libs

Originally committed as revision 12248 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavfilter/avfilter.h

@@ -22,7 +22,17 @@
 #ifndef FFMPEG_AVFILTER_H
 #define FFMPEG_AVFILTER_H
 
-#define LIBAVFILTER_VERSION      0.0.0
+#define LIBAVFILTER_VERSION_MAJOR  0
+#define LIBAVFILTER_VERSION_MINOR  0
+#define LIBAVFILTER_VERSION_MICRO  0
+
+#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
+                                               LIBAVFILTER_VERSION_MINOR, \
+                                               LIBAVFILTER_VERSION_MICRO)
+#define LIBAVFILTER_VERSION     AV_VERSION(LIBAVFILTER_VERSION_MAJOR,   \
+                                           LIBAVFILTER_VERSION_MINOR,   \
+                                           LIBAVFILTER_VERSION_MICRO)
+#define LIBAVFILTER_BUILD       LIBAVFILTER_VERSION_INT
 
 #include <stddef.h>
 #include "avcodec.h"