diff -up libvpd-2.1.3/src/helper_functions.cpp.gcc47 libvpd-2.1.3/src/helper_functions.cpp
--- libvpd-2.1.3/src/helper_functions.cpp.gcc47	2012-01-18 10:50:11.367639050 +0100
+++ libvpd-2.1.3/src/helper_functions.cpp	2012-01-18 10:52:22.453423299 +0100
@@ -24,6 +24,7 @@
 #include <libvpd-2/helper_functions.hpp>
 #include <cstdio>
 #include <fcntl.h>
+#include <unistd.h>
 #include <cstdlib>
 #include <cstring>
 #include <fstream>