Add road tile cached one way state, one way road section detection

src/saveload/afterload.cpp

@@ -3795,6 +3795,11 @@ bool AfterLoadGame()
 		}
 	}
 
+	if (SlXvIsFeatureMissing(XSLFI_ONE_WAY_ROAD_STATE)) {
+		extern void RecalculateRoadCachedOneWayStates();
+		RecalculateRoadCachedOneWayStates();
+	}
+
 	InitializeRoadGUI();
 
 	/* This needs to be done after conversion. */

src/saveload/extended_ver_sl.cpp

@@ -137,6 +137,7 @@ const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
 	{ XSLFI_MORE_VEHICLE_ORDERS,    XSCF_NULL,                1,   1, "more_veh_orders",           nullptr, nullptr, nullptr        },
 	{ XSLFI_ORDER_FLAGS_EXTRA,      XSCF_NULL,                1,   1, "order_flags_extra",         nullptr, nullptr, nullptr        },
 	{ XSLFI_ONE_WAY_DT_ROAD_STOP,   XSCF_NULL,                1,   1, "one_way_dt_road_stop",      nullptr, nullptr, nullptr        },
+	{ XSLFI_ONE_WAY_ROAD_STATE,     XSCF_NULL,                1,   1, "one_way_road_state",        nullptr, nullptr, nullptr        },
 	{ XSLFI_NULL, XSCF_NULL, 0, 0, nullptr, nullptr, nullptr, nullptr },// This is the end marker
 };
 

src/saveload/extended_ver_sl.h

@@ -91,6 +91,7 @@ enum SlXvFeatureIndex {
 	XSLFI_MORE_VEHICLE_ORDERS,                    ///< More vehicle orders - VehicleOrderID is 16 bits instead of 8
 	XSLFI_ORDER_FLAGS_EXTRA,                      ///< Order flags field extra size
 	XSLFI_ONE_WAY_DT_ROAD_STOP,                   ///< One-way drive-through road stops
+	XSLFI_ONE_WAY_ROAD_STATE,                     ///< One-way road state cache
 
 	XSLFI_RIFF_HEADER_60_BIT,                     ///< Size field in RIFF chunk header is 60 bit
 	XSLFI_HEIGHT_8_BIT,                           ///< Map tile height is 8 bit instead of 4 bit, but savegame version may be before this became true in trunk