Signals update to power_change() (#21421)

As title. Makes area/power_change() and area on_enter/on_exit procs both
rely on signals for machinery handling where they draw power from.

Author: Batrachophreno

code/game/area/area_power.dm

@@ -26,12 +26,6 @@
 /area/proc/power_change()
 	SEND_SIGNAL(src, COMSIG_AREA_POWER_CHANGE)
 
-	//One day, this will only use the signal, but that day is not today
-	for(var/obj/machinery/M in src)	// for each machine in the area
-		M.power_change()			// reverify power status (to update icons etc.)
-	if (fire || eject || party)
-		update_icon()
-
 /area/proc/usage(var/chan)
 	switch(chan)
 		if(AREA_USAGE_LIGHT)

code/game/machinery/alarm.dm

@@ -404,6 +404,7 @@ pixel_x = 10;
 	return ..()
 
 /obj/machinery/alarm/LateInitialize()
+	. = ..()
 	apply_mode()
 
 /obj/machinery/alarm/Initialize(mapload, var/dir, var/building = 0)

code/game/machinery/atmoalter/portable_atmospherics.dm

@@ -34,6 +34,7 @@
 	return INITIALIZE_HINT_LATELOAD
 
 /obj/machinery/portable_atmospherics/canister/LateInitialize()
+	. = ..()
 	update_icon()
 
 /obj/machinery/portable_atmospherics/process()

code/game/machinery/autolathe/autolathe.dm

@@ -56,6 +56,7 @@
 	return INITIALIZE_HINT_LATELOAD
 
 /obj/machinery/autolathe/LateInitialize()
+	. = ..()
 	populate_lathe_recipes()
 
 /obj/machinery/autolathe/Destroy()

code/game/machinery/bluespace_drive.dm

@@ -113,6 +113,7 @@
 	return INITIALIZE_HINT_LATELOAD
 
 /obj/machinery/bluespacedrive/LateInitialize()
+	. = ..()
 	if(SSatlas.current_map.use_overmap && !linked)
 		var/my_sector = GLOB.map_sectors["[z]"]
 		if(istype(my_sector, /obj/effect/overmap/visitable/ship))
@@ -496,6 +497,7 @@
 	return INITIALIZE_HINT_LATELOAD
 
 /obj/machinery/computer/bluespacedrive/LateInitialize()
+	. = ..()
 
 	linked_bluespace_drive = locate() in get_area(src)
 

code/game/machinery/computer/pod.dm

@@ -19,6 +19,7 @@
 	. = INITIALIZE_HINT_LATELOAD
 
 /obj/machinery/computer/pod/LateInitialize()
+	. = ..()
 	for(var/obj/machinery/mass_driver/M in SSmachinery.machinery)
 		if(M.id == id)
 			connected = M

code/game/machinery/distress_button.dm

@@ -9,6 +9,7 @@
 	return INITIALIZE_HINT_LATELOAD
 
 /obj/machinery/button/distress/LateInitialize()
+	. = ..()
 	if(SSatlas.current_map.use_overmap && !linked)
 		var/my_sector = GLOB.map_sectors["[z]"]
 		if (istype(my_sector, /obj/effect/overmap/visitable))

code/game/machinery/doors/brigdoors.dm

@@ -36,6 +36,7 @@
 	return INITIALIZE_HINT_LATELOAD
 
 /obj/machinery/door_timer/LateInitialize()
+	. = ..()
 	for(var/obj/machinery/door/airlock/glass_security/D in SSmachinery.machinery)
 		if(D.id_tag == src.id) // Airlocks use "id_tag" instead of "id".
 			targets += D

code/game/machinery/firealarm.dm

@@ -18,6 +18,7 @@
 	var/seclevel
 	///looping sound datum for our fire alarm siren.
 	var/datum/looping_sound/firealarm/soundloop
+	always_area_sensitive = TRUE
 
 /obj/machinery/firealarm/Initialize(mapload, var/dir, var/building = 0)
 	. = ..(mapload)

code/game/machinery/machinery.dm

@@ -149,6 +149,10 @@ Class Procs:
 	 */
 	var/manufacturer = null
 
+	///Do we want to hook into on_enter_area and on_exit_area?
+	///Disables some optimizations
+	var/always_area_sensitive = FALSE
+
 /obj/machinery/feedback_hints(mob/user, distance, is_adjacent)
 	. = list()
 	if(signaler && is_adjacent)
@@ -190,6 +194,8 @@ Class Procs:
 		if(component_parts.len)
 			RefreshParts()
 
+	return INITIALIZE_HINT_LATELOAD
+
 /obj/machinery/Destroy()
 	//Stupid macro used in power usage
 	CAN_BE_REDEFINED(TRUE)