Make AVCodec long_names definition conditional depending on CONFIG_SMALL.

Originally committed as revision 13759 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/shorten.c

@@ -532,5 +532,5 @@ AVCodec shorten_decoder = {
     shorten_decode_close,
     shorten_decode_frame,
     .flush= shorten_flush,
-    .long_name= "Shorten",
+    .long_name= NULL_IF_CONFIG_SMALL("Shorten"),
 };