--- src/flow-header.c.orig	2009-01-14 12:22:56.000000000 +0800
+++ src/flow-header.c	2009-01-14 12:23:05.000000000 +0800
@@ -32,6 +32,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
 
 void usage(void);