diff --git a/src/Base/Unit.cpp b/src/Base/Unit.cpp
index bf00f2aa8..e2fb01c23 100644
--- a/src/Base/Unit.cpp
+++ b/src/Base/Unit.cpp
@@ -22,6 +22,8 @@
 
 #include "PreCompiled.h"
 #ifndef _PreComp_
+# include <sstream>
+# include <stdlib.h>
 #endif
 
 #include "Unit.h"