NewGRF: Add/extend station variables for station info of nearby tiles

In preparation for support of more than 255 stations per GRF

src/newgrf_extension.h

@@ -76,7 +76,9 @@ enum Action0RemapPropertyIds {
 
 
 enum Action2VariableRemapIds {
-	A2VRI_OBJECT_FOUNDATION_SLOPE = 0x100,
+	A2VRI_STATION_INFO_NEARBY_TILES_EXT = 0x100,
+	A2VRI_STATION_INFO_NEARBY_TILES_V2,
+	A2VRI_OBJECT_FOUNDATION_SLOPE,
 	A2VRI_OBJECT_FOUNDATION_SLOPE_CHANGE,
 	A2VRI_VEHICLE_CURRENT_SPEED_SCALED,
 	A2VRI_ROADSTOP_INFO_NEARBY_TILES_EXT,
@@ -107,6 +109,7 @@ enum GRFFeatureTestObservationFlag : uint8 {
 	GFTOF_MORE_VARACTION2_TYPES,
 	GFTOF_MULTI_PART_SHIPS,
 	GFTOF_ROAD_STOPS,
+	GFTOF_STATION_VAR68_EXT_LOCALIDX,
 
 	GFTOF_INVALID = 0xFF,
 };