Merge pull request #13400 from silicons/shields

adds two procs to find exterior tiles for projecting hull shields around for later pr

code/game/area/Space_Station_13_areas.dm

@@ -43,6 +43,7 @@ NOTE: there are two lists of areas in the end of this file: centcom and station
 	outdoors = TRUE
 	ambientsounds = SPACE
 	blob_allowed = FALSE //Eating up space doesn't count for victory as a blob.
+	considered_hull_exterior = TRUE
 
 /area/space/nearstation
 	icon_state = "space_near"
@@ -1592,4 +1593,4 @@ NOTE: there are two lists of areas in the end of this file: centcom and station
 	valid_territory = FALSE
 	outdoors = TRUE
 	ambientsounds = SPACE
-	blob_allowed = FALSE //While part of the station, what good will it do you?
+	blob_allowed = FALSE //While part of the station, what good will it do you?

code/game/area/areas.dm

@@ -34,6 +34,9 @@
 	/// If megafauna can be spawned by natural random generation
 	var/megafauna_spawn_allowed = FALSE
 
+	/// Considered space for hull shielding
+	var/considered_hull_exterior = FALSE
+
 	var/fire = null
 	var/atmos = TRUE
 	var/atmosalm = FALSE