1 files changed, 1 insertions, 1 deletions
diff --git a/src/gui.h b/src/gui.h
index f91ea849e..96660bb09 100644
--- a/src/gui.h
+++ b/src/gui.h
@@ -57,7 +57,7 @@ void ShowShipViewWindow(const Vehicle *v);
 void ShowBuildAirToolbar(void);
 
 /* terraform_gui.c */
-void ShowTerraformToolbar(void);
+void ShowTerraformToolbar(Window *link = NULL);
 
 /* tgp_gui.c */
 void ShowGenerateLandscape(void);