use clone-node method to redefine apple

(only way to add a new group item, for compat with rubenwardy's food mod)

init.lua

@@ -52,6 +52,17 @@ else
 end
 moretrees.intllib = S
 
+-- clone node
+
+function moretrees.clone_node(name)
+	local node2 = {}
+	local node = minetest.registered_nodes[name]
+	for k,v in pairs(node) do
+		node2[k]=v
+	end
+	return node2
+end
+
 -- infinite stacks checking
 
 if minetest.get_modpath("unified_inventory") or not minetest.setting_getbool("creative_mode") then

node_defs.lua

@@ -374,9 +374,9 @@ minetest.register_node("moretrees:fir_leaves_bright", {
 })
 
 if moretrees.enable_redefine_apple then
-	minetest.override_item("default:apple",
+	local appledef = moretrees.clone_node("default:apple")
-		{groups = { fleshy=3, dig_immediate=3, flammable=2, leafdecay=3, leafdecay_drop=1, attached_node = 1}
+	appledef.groups.attached_node = 1
-	})
+	minetest.register_node(":default:apple", appledef)
 end
 
 table.insert(moretrees.avoidnodes, "default:jungletree")