games/openbor: unbreak with GCC 4.2

cc1: error: unrecognized command line option "-Wno-unused-result"

Reported by:	pkg-fallout

games/openbor/Makefile

@@ -81,6 +81,7 @@ post-patch:
 	@${REINPLACE_CMD} -e 's/ -O[0-9]//; s/ -g//; s/ -Werror//' \
 		-e 's/ -fomit-frame-pointer//' \
 		-e 's/ -freorder-blocks//' \
+		-e 's/ -Wno-unused-result//' \
 		-e 's/ -Wl,-rpath,$$(LIBRARIES)//' \
 		-e '/echo/!s/	@/	/' \
 		-e 's/@echo/@$$(ECHO)/' \