--- demos/FFConsoleDemo.cpp.orig	Sun Apr  9 22:15:21 2017
+++ demos/FFConsoleDemo.cpp	Sun Apr  9 22:15:43 2017
@@ -1,6 +1,7 @@
 #include "OIS.h"
 
 #include <math.h>
+#include <unistd.h>
 #include <cstdlib>
 #include <iostream>
 #include <iomanip>
