diff --git a/src/genworld_gui.cpp b/src/genworld_gui.cpp
--- a/src/genworld_gui.cpp
+++ b/src/genworld_gui.cpp
@@ -29,6 +29,7 @@
 #include "settings_func.h"
 #include "core/geometry_func.hpp"
 #include "core/random_func.hpp"
+#include "progress.h"
 
 #include "table/strings.h"
 #include "table/sprites.h"