--- a/Empire/Diplomacy.h
+++ b/Empire/Diplomacy.h
@@ -1,6 +1,7 @@
 #ifndef _Diplomacy_h_
 #define _Diplomacy_h_
 
+#include <cstdint>
 #include <string>
 #include <boost/serialization/access.hpp>
 #include "../util/Enum.h"
--- a/universe/Enums.h
+++ b/universe/Enums.h
@@ -2,6 +2,7 @@
 #define _Enums_h_
 
 
+#include <cstdint>
 #include <iostream>
 #include <map>
 #include <string>
