lavc: add libdcadec decoder

Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavcodec/allcodecs.c

@@ -442,6 +442,7 @@ void avcodec_register_all(void)
     REGISTER_ENCDEC (XSUB,              xsub);
 
     /* external libraries */
+    REGISTER_DECODER(LIBDCADEC,         libdcadec)
     REGISTER_ENCODER(LIBFAAC,           libfaac);
     REGISTER_ENCDEC (LIBFDK_AAC,        libfdk_aac);
     REGISTER_ENCDEC (LIBGSM,            libgsm);