unsigned long support: conversion routines
diff --git a/skeletons/asn_system.h b/skeletons/asn_system.h
index fe69645..193a975 100644
--- a/skeletons/asn_system.h
+++ b/skeletons/asn_system.h
@@ -17,6 +17,7 @@
 #include <stdlib.h>	/* For *alloc(3) */
 #include <string.h>	/* For memcpy(3) */
 #include <sys/types.h>	/* For size_t */
+#include <limits.h>	/* For LONG_MAX */
 #include <stdarg.h>	/* For va_start */
 #include <stddef.h>	/* for offsetof and ptrdiff_t */