Merge branch 'master' into jgrpp

# Conflicts:
#	src/airport_gui.cpp
#	src/blitter/32bpp_optimized.cpp
#	src/blitter/32bpp_simple.cpp
#	src/blitter/32bpp_sse2.cpp
#	src/blitter/8bpp_optimized.cpp
#	src/blitter/8bpp_simple.cpp
#	src/blitter/null.cpp
#	src/build_vehicle_gui.cpp
#	src/company_gui.cpp
#	src/crashlog.cpp
#	src/dropdown.cpp
#	src/dropdown_type.h
#	src/genworld_gui.cpp
#	src/gfx.cpp
#	src/main_gui.cpp
#	src/newgrf_debug_gui.cpp
#	src/news_gui.cpp
#	src/news_type.h
#	src/openttd.cpp
#	src/order_gui.cpp
#	src/settings.cpp
#	src/settings_gui.cpp
#	src/signs.cpp
#	src/smallmap_gui.cpp
#	src/spritecache.cpp
#	src/spriteloader/grf.cpp
#	src/texteff.cpp
#	src/toolbar_gui.cpp
#	src/town_cmd.cpp
#	src/vehicle.cpp
#	src/vehicle_gui.cpp
#	src/video/opengl.cpp
#	src/viewport.cpp
#	src/waypoint_cmd.cpp
#	src/zoom_type.h

src/genworld_gui.cpp

@@ -20,6 +20,7 @@
 #include "string_func.h"
 #include "gui.h"
 #include "dropdown_type.h"
+#include "dropdown_common_type.h"
 #include "dropdown_func.h"
 #include "querystring_gui.h"
 #include "town.h"
@@ -392,7 +393,7 @@ static DropDownList BuildMapsizeDropDown(int other_dimension)
 
 	for (uint i = MIN_MAP_SIZE_BITS; i <= MAX_MAP_SIZE_BITS; i++) {
 		SetDParam(0, 1LL << i);
-		list.push_back(std::make_unique<DropDownListStringItem>((i + other_dimension > MAX_MAP_TILES_BITS) ? STR_RED_INT : STR_JUST_INT, i, false));
+		list.push_back(MakeDropDownListStringItem((i + other_dimension > MAX_MAP_TILES_BITS) ? STR_RED_INT : STR_JUST_INT, i, false));
 	}
 
 	return list;
@@ -405,20 +406,20 @@ static DropDownList BuildTownNameDropDown()
 	/* Add and sort newgrf townnames generators */
 	const auto &grf_names = GetGRFTownNameList();
 	for (uint i = 0; i < grf_names.size(); i++) {
-		list.push_back(std::make_unique<DropDownListStringItem>(grf_names[i], BUILTIN_TOWNNAME_GENERATOR_COUNT + i, false));
+		list.push_back(MakeDropDownListStringItem(grf_names[i], BUILTIN_TOWNNAME_GENERATOR_COUNT + i));
 	}
 	std::sort(list.begin(), list.end(), DropDownListStringItem::NatSortFunc);
 
 	size_t newgrf_size = list.size();
 	/* Insert newgrf_names at the top of the list */
 	if (newgrf_size > 0) {
-		list.push_back(std::make_unique<DropDownListDividerItem>(-1, false)); // separator line
+		list.push_back(MakeDropDownListDividerItem()); // separator line
 		newgrf_size++;
 	}
 
 	/* Add and sort original townnames generators */
 	for (uint i = 0; i < BUILTIN_TOWNNAME_GENERATOR_COUNT; i++) {
-		list.push_back(std::make_unique<DropDownListStringItem>(STR_MAPGEN_TOWN_NAME_ORIGINAL_ENGLISH + i, i, false));
+		list.push_back(MakeDropDownListStringItem(STR_MAPGEN_TOWN_NAME_ORIGINAL_ENGLISH + i, i));
 	}
 	std::sort(list.begin() + newgrf_size, list.end(), DropDownListStringItem::NatSortFunc);