Fix compilation with VC-1 decoder disabled.

Originally committed as revision 7149 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/Makefile

@@ -157,7 +157,7 @@ OBJS-$(CONFIG_VQA_DECODER)             += vqavideo.o
 OBJS-$(CONFIG_WAVPACK_DECODER)         += wavpack.o
 OBJS-$(CONFIG_WMAV1_DECODER)           += wmadec.o
 OBJS-$(CONFIG_WMAV2_DECODER)           += wmadec.o
-OBJS-$(CONFIG_WMV3_DECODER)            += vc1.o
+OBJS-$(CONFIG_WMV3_DECODER)            += vc1.o vc1dsp.o
 OBJS-$(CONFIG_WNV1_DECODER)            += wnv1.o
 OBJS-$(CONFIG_WS_SND1_DECODER)         += ws-snd1.o
 OBJS-$(CONFIG_XAN_DPCM_DECODER)        += dpcm.o