Index: Tool.cpp
--- Tool.cpp.orig
+++ Tool.cpp
@@ -1,6 +1,7 @@
 #include "Tool.h"
 #include <gdk/gdkkeysyms.h>
 #include "main.h"
+#include <cstdlib>
 
 const float ZoomInTool::ZOOM_BOX_WIDTH = 0.35;