attack if in range of any cell of a building

OpenRA.Mods.RA/TargetableBuilding.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA
+{
+	class TargetableBuildingInfo : TargetableInfo, ITraitPrerequisite<BuildingInfo>
+	{
+		public override object Create( ActorInitializer init ) { return new TargetableBuilding( this ); }
+	}
+
+	class TargetableBuilding : Targetable
+	{
+		public TargetableBuilding( TargetableBuildingInfo info )
+			: base( info )
+		{
+		}
+
+		public override IEnumerable<int2> TargetableSquares( Actor self )
+		{
+			return self.Trait<Building>().OccupiedCells();
+		}
+	}
+}