--- openttd-1.5.3/src/safeguards.h.orig	2016-02-02 16:21:10.378533175 +0000
+++ openttd-1.5.3/src/safeguards.h	2016-02-02 16:21:15.269555568 +0000
@@ -21,6 +21,8 @@
 #ifndef SAFEGUARDS_H
 #define SAFEGUARDS_H
 
+#include <stdlib.h>
+
 /* Use MallocT instead. */
 #define malloc    SAFEGUARD_DO_NOT_USE_THIS_METHOD