Move dependency generation commands into configure.

This will allow specifying gcc-independent commands in the future.

Originally committed as revision 12426 to svn://svn.ffmpeg.org/ffmpeg/trunk

common.mak

@@ -61,9 +61,8 @@ $(SLIBNAME_WITH_MAJOR): $(OBJS)
 ALLHEADERS = $(subst $(LIBSRC)/,,$(wildcard $(LIBSRC)/*.h))
 checkheaders: $(filter-out %_template.ho,$(ALLHEADERS:.h=.ho))
 
-# gcc stupidly only outputs the basename of targets with -MM
 depend dep: $(SRCS)
-	$(CC) -MM $(CFLAGS) $^ | sed 's,[0-9a-z._-]*: \([a-z0-9]*/\).*,\1&,' > .depend
+	$(DEPEND_CMD) > .depend
 
 clean::
 	rm -f *.o *~ *.a *.lib *.so *.so.* *.dylib *.dll \