Merge branch 'master' into jgrpp

# Conflicts:
#	src/3rdparty/fmt/core.h
#	src/command_type.h
#	src/console_cmds.cpp
#	src/core/overflowsafe_type.hpp
#	src/landscape.cpp
#	src/network/network.cpp
#	src/newgrf_object.h
#	src/object_cmd.cpp
#	src/order_gui.cpp
#	src/saveload/vehicle_sl.cpp
#	src/script/api/script_industrytype.cpp
#	src/script/api/script_object.hpp
#	src/script/api/script_town.cpp
#	src/table/object_land.h
#	src/timetable_cmd.cpp
#	src/tree_cmd.cpp
#	src/vehicle_gui.cpp
#	src/window.cpp

src/linkgraph/linkgraph_gui.cpp

@@ -721,7 +721,7 @@ LinkGraphLegendWindow::LinkGraphLegendWindow(WindowDesc *desc, int window_number
 {
 	this->InitNested(window_number);
 	this->InvalidateData(0);
-	this->SetOverlay(FindWindowById(WC_MAIN_WINDOW, 0)->viewport->overlay);
+	this->SetOverlay(GetMainWindow()->viewport->overlay);
 }
 
 /**