include sys/stat.h, needed for S_IRUSR and S_IWUSR

--- highscore.cc.orig	Wed Oct 22 21:22:24 2014
+++ highscore.cc	Wed Oct 22 21:22:59 2014
@@ -20,6 +20,7 @@
 #include "decl.h"
 #include "screen.h"
 
+#include <sys/stat.h>
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
