Add ValidStances checks to BlocksProjectiles and Gate.

OpenRA.Mods.Common/Traits/Buildings/Gate.cs

@@ -30,6 +30,9 @@ namespace OpenRA.Mods.Common.Traits
 		[Desc("Blocks bullets scaled to open value.")]
 		public readonly WDist BlocksProjectilesHeight = new WDist(640);
 
+		[Desc("Determines what projectiles to block based on their allegiance to the gate owner.")]
+		public readonly PlayerRelationship BlocksProjectilesValidRelationships = PlayerRelationship.Ally | PlayerRelationship.Neutral | PlayerRelationship.Enemy;
+
 		public override object Create(ActorInitializer init) { return new Gate(init, this); }
 	}
 
@@ -137,5 +140,7 @@ namespace OpenRA.Mods.Common.Traits
 		}
 
 		WDist IBlocksProjectiles.BlockingHeight => new WDist(Info.BlocksProjectilesHeight.Length * (OpenPosition - Position) / OpenPosition);
+
+		PlayerRelationship IBlocksProjectiles.ValidRelationships => Info.BlocksProjectilesValidRelationships;
 	}
 }