diff -Nurd -x'*~' QCheckers.orig/checkersstate.h QCheckers/checkersstate.h
--- QCheckers.orig/checkersstate.h	2009-12-27 10:37:57.000000000 -0500
+++ QCheckers/checkersstate.h	2012-03-24 05:08:33.000000000 -0400
@@ -1,6 +1,7 @@
 #ifndef CHECKERSSTATE_H
 #define CHECKERSSTATE_H
 
+#include <sys/types.h>
 #include <cstdlib>
 #include <cstring>
 #include <iostream>