Check 3 nodes above for enderman spawn

mods/ENTITIES/mobs_mc/enderman.lua

@@ -257,6 +257,9 @@ mcl_mobs:register_mob("mobs_mc:enderman", {
 	},
 	animation = select_enderman_animation("normal"),
 	_taken_node = "",
+	can_spawn = function(pos)
+		return #minetest.find_nodes_in_area(vector.offset(pos,0,1,0),vector.offset(pos,0,3,0),{"air"}) > 2
+	end,
 	do_custom = function(self, dtime)
 		-- PARTICLE BEHAVIOUR HERE.
 		local enderpos = self.object:get_pos()