Enable building r3d demuxer when its config is set.

Originally committed as revision 16696 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/Makefile

@@ -149,6 +149,7 @@ OBJS-$(CONFIG_PCM_U8_DEMUXER)            += raw.o
 OBJS-$(CONFIG_PCM_U8_MUXER)              += raw.o
 OBJS-$(CONFIG_PSP_MUXER)                 += movenc.o riff.o isom.o avc.o
 OBJS-$(CONFIG_PVA_DEMUXER)               += pva.o
+OBJS-$(CONFIG_R3D_DEMUXER)               += r3d.o
 OBJS-$(CONFIG_RAWVIDEO_DEMUXER)          += raw.o
 OBJS-$(CONFIG_RAWVIDEO_MUXER)            += raw.o
 OBJS-$(CONFIG_REDIR_DEMUXER)             += rtsp.o