fix dependency generation

Originally committed as revision 13820 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -969,7 +969,7 @@ SLIBNAME_WITH_MAJOR='$(SLIBNAME).$(LIBMAJOR)'
 LIB_INSTALL_EXTRA_CMD='$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
 
 # gcc stupidly only outputs the basename of targets with -MM
-DEPEND_CMD='$(CC) $(CFLAGS) -MM -MG $< | sed -e "/^\#.*/d" -e "1s,^,$(@D)/," -e "s,[[:space:]]version\\.h,\$$(BUILD_ROOT_REL)/&,"'
+DEPEND_CMD='$(CC) $(CFLAGS) -MM -MG $< | sed -e "/^\#.*/d" -e "1s,^,$(@D)/," -e "s,\\([[:space:]]\\)\\(version\\.h\\),\\1\$$(BUILD_ROOT_REL)/\\2,"'
 
 # find source path
 source_path="`dirname \"$0\"`"