diff -ru libmsn-4.2.1.orig/msn/util.cpp libmsn-4.2.1/msn/util.cpp
--- libmsn-4.2.1.orig/msn/util.cpp	2012-04-18 19:02:12.447876971 +0200
+++ libmsn-4.2.1/msn/util.cpp	2012-04-18 19:02:36.460762835 +0200
@@ -30,6 +30,7 @@
 #include <openssl/rand.h>
 #include <cstring>
 #include <sys/timeb.h>
+#include <unistd.h>
 #include "md5.h"
 #include "libsiren/siren7.h"