Allow to clear name with anvil

mods/ITEMS/mcl_anvils/init.lua

@@ -31,7 +31,9 @@ local function update_anvil_slots(meta)
 
 	-- Just rename
 	if (not input1:is_empty() and input2:is_empty()) or (input1:is_empty() and not input2:is_empty()) then
-		if new_name ~= nil and new_name ~= "" then
+		if new_name == nil then
+			new_name = ""
+		end
 		local name_item
 		if input1:is_empty() then
 			name_item = input2
@@ -54,9 +56,6 @@ local function update_anvil_slots(meta)
 	else
 		new_output = ""
 	end
-	else
-		new_output = ""
-	end
 
 	-- Set the new output slot
 	if new_output ~= nil then