--- mkcostab.c.orig	1997-12-08 17:56:06.000000000 +0100
+++ mkcostab.c	2010-10-20 06:20:08.000000000 +0200
@@ -23,6 +23,7 @@
 
 #include <math.h>
 #include <stdio.h>
+#include <stdlib.h> /* exit() */
 
 /* ---------------------------------------------------------------------- */
 
--- xdisplay.c.orig	1997-12-08 17:56:06.000000000 +0100
+++ xdisplay.c	2010-10-20 06:19:37.000000000 +0200
@@ -36,6 +36,7 @@
 #include <X11/X.h>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
+#include <stdlib.h> /* abort() exit() */
 
 /* ---------------------------------------------------------------------- */