$OpenBSD$

Fix build error

Index: Makefile.skel
--- Makefile.skel.orig
+++ Makefile.skel
@@ -86,7 +86,7 @@ nwcc: $(CCOBJ) $(CC1OBJ) $(SNAKEOBJ) $(SWEEPEROBJ) lib
 	$(CC) $(CFLAGS) $(SNAKEOBJ) -o snake -lpthread
 	$(CC) $(CFLAGS) $(SWEEPEROBJ) -o sweeper
 	make $(BUILDCPP)
-	./nwcc -write-fcat
+	-./nwcc -write-fcat
 	:
 	: All done, you may type "make install" now!
 	: You should also do "make test" to ensure that
