diff --git a/src/gui.h b/src/gui.h
--- a/src/gui.h
+++ b/src/gui.h
@@ -8,6 +8,7 @@
 #include "window_type.h"
 #include "vehicle_type.h"
 #include "gfx_type.h"
+#include "economy_type.h"
 
 /* main_gui.cpp */
 void CcPlaySound10(bool success, TileIndex tile, uint32 p1, uint32 p2);