diff --git a/src/saveload/saveload_internal.h b/src/saveload/saveload_internal.h
--- a/src/saveload/saveload_internal.h
+++ b/src/saveload/saveload_internal.h
@@ -45,6 +45,7 @@ void CopyTempEngineData();
 
 extern int32 _saved_scrollpos_x;
 extern int32 _saved_scrollpos_y;
+extern ZoomLevelByte _saved_scrollpos_zoom;
 
 extern SavegameType _savegame_type;
 extern uint32 _ttdp_version;