(svn r8767) -Fix

-Codechange: Do not hardcode the catchment radius of airports, but hold the information in AirportFTAClass
-Fix (r979): The default AI tested possible airport locations with a fixed catchment radius instead of the radius of the to be built airport

src/ai/default/default.cpp

@@ -3333,19 +3333,13 @@ static int32 AiDoBuildDefaultAirportBlock(TileIndex tile, const AiDefaultBlockDa
 static bool AiCheckAirportResources(TileIndex tile, const AiDefaultBlockData *p, byte cargo)
 {
 	uint values[NUM_CARGO];
-	int rad;
-
-	if (_patches.modified_catchment) {
-		rad = CA_AIR_LARGE; // I Have NFI what airport the
-	} else { // AI is going to build here
-		rad = 4;
-	}
 
 	for (; p->mode == 0; p++) {
 		TileIndex tile2 = TILE_ADD(tile, ToTileIndexDiff(p->tileoffs));
 		const AirportFTAClass* airport = GetAirport(p->attr);
 		uint w = airport->size_x;
 		uint h = airport->size_y;
+		uint rad = _patches.modified_catchment ? airport->catchment : 4;
 
 		if (cargo & 0x80) {
 			GetProductionAroundTiles(values, tile2, w, h, rad);