diff --git a/ship_cmd.c b/ship_cmd.c
--- a/ship_cmd.c
+++ b/ship_cmd.c
@@ -1,6 +1,7 @@
 #include "stdafx.h"
 #include "openttd.h"
 #include "table/strings.h"
+#include "functions.h"
 #include "map.h"
 #include "tile.h"
 #include "vehicle.h"