remove #![feature(extern_crate_item_prelude)]

crate/memory/src/lib.rs

@@ -1,7 +1,6 @@
 #![cfg_attr(not(test), no_std)]
 #![feature(alloc)]
 #![feature(nll)]
-#![feature(extern_crate_item_prelude)]
 
 // import macros from log
 use log::*;

crate/process/src/lib.rs

@@ -6,7 +6,6 @@
 #![feature(vec_resize_default)]
 #![feature(asm)]
 #![feature(exact_size_is_empty)]
-#![feature(extern_crate_item_prelude)]
 
 extern crate alloc;
 

kernel/src/lib.rs

@@ -5,7 +5,6 @@
 #![feature(optin_builtin_traits)]
 #![feature(panic_info_message)]
 #![feature(global_asm)]
-#![feature(extern_crate_item_prelude)]
 #![no_std]
 
 // just keep it ...