Add option to disable lavacooling (#1726)

functions.lua

@@ -131,7 +131,8 @@ default.cool_lava = function(pos, node)
 		{pos = pos, max_hear_distance = 16, gain = 0.25})
 end
 
-minetest.register_abm({
+if minetest.setting_getbool("enable_lavacooling") ~= false then
+	minetest.register_abm({
 		label = "Lava cooling",
 		nodenames = {"default:lava_source", "default:lava_flowing"},
 		neighbors = {"group:cools_lava", "group:water"},
@@ -141,8 +142,8 @@ minetest.register_abm({
 		action = function(...)
 			default.cool_lava(...)
 		end,
-})
-
+	})
+end
 
 --
 -- optimized helper to put all items in an inventory into a drops list