Fix timefilter test program build without previously building libavformat.

The test program depends on symbols from this library.

Originally committed as revision 18247 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/Makefile

@@ -248,4 +248,4 @@ TESTPROGS = timefilter
 
 include $(SUBDIR)../subdir.mak
 
-$(SUBDIR)output-example$(EXESUF): $(FF_DEP_LIBS)
+$(SUBDIR)output-example$(EXESUF) $(SUBDIR)timefilter-test$(EXESUF): $(FF_DEP_LIBS)