Moved borer hud onto /datum/hud/animal/borer.

Debugging/updating some borer HUD code.

Changing borer hud from animal/borer to borer.

Fixing borers and tidying a spelling mistake.

Collapsing HUD icons into the base hud handler where possible.

Moving HUD icon definitions onto the HUD datum.

Collapsing handle_regular_hud_updates().

Declifying hud elements.

Moving human attack selector onto HUD.

Converting HUD icon update logic into the decl system.

Updating mob Life() to update HUD icons.

Cleaning up/refactoring some HUD var code.

Converting gun mode to the decl system.

Updating borer HUD.

Refactoring last_special.

General max health refactor.

Testing/refining HUD rewrite.

Moving all the status and hunger icons into the screen icon files.

Breaking up the screen icons.

Adding istype checks to hud_used.

Post-rebase update to zone selectors and borer huds.

Converting ability_master to /datum/hud.

LAZYLISTs screen.

code/__defines/hud.dm

@@ -0,0 +1,4 @@
+#define CLEAR_HUD_ALERTS(M)        if(istype(M?.hud_used) && M.hud_used.alerts)                    { M.hud_used.alerts = null; }
+#define SET_HUD_ALERT(M, A, V)     if(istype(M?.hud_used))                                         { LAZYSET(M.hud_used.alerts, A, V); }
+#define SET_HUD_ALERT_MIN(M, A, V) if(istype(M?.hud_used) && V < LAZYACCESS(M.hud_used.alerts, A)) { LAZYSET(M.hud_used.alerts, A, V); }
+#define SET_HUD_ALERT_MAX(M, A, V) if(istype(M?.hud_used) && V > LAZYACCESS(M.hud_used.alerts, A)) { LAZYSET(M.hud_used.alerts, A, V); }

code/_onclick/click.dm

@@ -351,8 +351,8 @@ var/global/list/click_catchers
 	return global.click_catchers
 
 /obj/screen/click_catcher
-	icon = 'icons/mob/screen_gen.dmi'
-	icon_state = "click_catcher"
+	icon = 'icons/mob/screen/fill.dmi'
+	icon_state = "blank"
 	plane = CLICKCATCHER_PLANE
 	mouse_opacity = 2
 	screen_loc = "CENTER-7,CENTER-7"

code/_onclick/hud/_defines.dm

@@ -74,7 +74,6 @@
 #define ui_up_hint "RIGHT-1:28,TOP-1:29"
 #define ui_toxin "RIGHT-1:28,TOP-2:27"
 #define ui_fire "RIGHT-1:28,TOP-3:25"
-#define ui_oxygen "RIGHT-1:28,TOP-4:23"
 #define ui_pressure "RIGHT-1:28,TOP-5:21"
 
 #define ui_alien_toxin "RIGHT-1:28,TOP-2:25"