diff --git a/src/ship_gui.cpp b/src/ship_gui.cpp
--- a/src/ship_gui.cpp
+++ b/src/ship_gui.cpp
@@ -15,6 +15,7 @@
 #include "newgrf_engine.h"
 #include "strings_func.h"
 #include "vehicle_func.h"
+#include "order_func.h"
 
 #include "table/strings.h"
 #include "table/sprites.h"