--- gnuchess-4.0.pl80/src/gnuan.c.orig	1999-04-02 22:58:53.000000000 -0500
+++ gnuchess-4.0.pl80/src/gnuan.c	2004-04-21 19:36:04.000000000 -0400
@@ -69,6 +69,7 @@
 #include <ctype.h>
 #include <signal.h>
 #include <fcntl.h>
+#include <errno.h>
 #ifdef MSDOS
 #include <dos.h>
 /*#include <conio.h>*/