--- /dev/null
+Index: ckermit/ckupty.c
+===================================================================
+--- ckermit.orig/ckupty.c 2012-05-08 04:43:50.000000000 +0100
++++ ckermit/ckupty.c 2012-05-08 04:44:30.000000000 +0100
+@@ -54,6 +54,8 @@
+ . HP-UX 8.00 and earlier (no vhangup or ptsname routines)
+ */
+
++#define _XOPEN_SOURCE
++#include <stdlib.h>
+ #include "ckcsym.h"
+ #include "ckcdeb.h" /* To pick up NETPTY definition */
+