only try to clear/redefine recipes for teleport and accel tube

if they are enabled in pipeworks' config

technic/crafts.lua

@@ -9,32 +9,36 @@ minetest.clear_craft({
 })
 
 -- Accelerator tube
-minetest.clear_craft({
+if pipeworks.enable_accelerator_tube then
+	minetest.clear_craft({
 		output = "pipeworks:accelerator_tube_1",
-})
+	})
 
--- Teleport tube
-minetest.clear_craft({
-	output = "pipeworks:teleport_tube_1",
-})
-
--- tubes crafting recipes
-
-minetest.register_craft({
+	minetest.register_craft({
 		output = 'pipeworks:accelerator_tube_1',
 		recipe = {
 			{'technic:copper_coil', 'pipeworks:tube_1', 'technic:copper_coil'},
 			}
-})
+	})
+end
 
-minetest.register_craft({
+-- Teleport tube
+if pipeworks.enable_teleport_tube then
+	minetest.clear_craft({
+		output = "pipeworks:teleport_tube_1",
+	})
+
+	minetest.register_craft({
 		output = 'pipeworks:teleport_tube_1',
 		recipe = {
 			{'default:mese_crystal', 'technic:copper_coil', 'default:mese_crystal'},
 			{'pipeworks:tube_1', 'technic:control_logic_unit', 'pipeworks:tube_1'},
 			{'default:mese_crystal', 'technic:copper_coil', 'default:mese_crystal'},
 			}
-})
+	})
+end
+
+-- tubes crafting recipes
 
 minetest.register_craft({
 	output = 'technic:diamond_drill_head',