Add: [Script] Let random road layout be a choice

src/script/api/ai_changelog.hpp

@@ -17,6 +17,9 @@
  *
  * This version is not yet released. The following changes are not set in stone yet.
  *
+ * API additions:
+ * \li AITown::ROAD_LAYOUT_RANDOM
+ *
  * \b 13.0
  *
  * API additions:

src/script/api/game_changelog.hpp

@@ -17,6 +17,9 @@
  *
  * This version is not yet released. The following changes are not set in stone yet.
  *
+ * API additions:
+ * \li GSTown::ROAD_LAYOUT_RANDOM
+ *
  * \b 13.0
  *
  * API additions:

src/script/api/script_town.cpp

@@ -288,7 +288,7 @@
 	EnforcePrecondition(false, size == TOWN_SIZE_SMALL || size == TOWN_SIZE_MEDIUM || size == TOWN_SIZE_LARGE)
 	EnforcePrecondition(false, size != TOWN_SIZE_LARGE || ScriptObject::GetCompany() == OWNER_DEITY);
 	if (ScriptObject::GetCompany() == OWNER_DEITY || _settings_game.economy.found_town == TF_CUSTOM_LAYOUT) {
-		EnforcePrecondition(false, layout == ROAD_LAYOUT_ORIGINAL || layout == ROAD_LAYOUT_BETTER_ROADS || layout == ROAD_LAYOUT_2x2 || layout == ROAD_LAYOUT_3x3);
+		EnforcePrecondition(false, layout >= ROAD_LAYOUT_ORIGINAL && layout <= ROAD_LAYOUT_RANDOM);
 	} else {
 		/* The layout parameter is ignored for AIs when custom layouts is disabled. */
 		layout = (RoadLayout) (byte)_settings_game.economy.town_layout;

src/script/api/script_town.hpp

@@ -98,6 +98,7 @@ public:
 		ROAD_LAYOUT_BETTER_ROADS  = ::TL_BETTER_ROADS, ///< Extended original algorithm (min. 2 distance between roads).
 		ROAD_LAYOUT_2x2           = ::TL_2X2_GRID,     ///< Geometric 2x2 grid algorithm
 		ROAD_LAYOUT_3x3           = ::TL_3X3_GRID,     ///< Geometric 3x3 grid algorithm
+		ROAD_LAYOUT_RANDOM        = ::TL_RANDOM,       ///< Random road layout
 
 		/* Custom added value, only valid for this API */
 		ROAD_LAYOUT_INVALID       = -1,                ///< The layout for invalid towns.