remove feature attributes for stable stuff

src/arch/x86_64/mod.rs

@@ -7,7 +7,6 @@ use super::common::{push, rust_trampoline};
 
 pub const STACK_ALIGN: usize = 16;
 
-#[allow(raw_pointer_derive)]
 #[derive(Debug)]
 pub struct Registers {
   rsp: *mut usize

src/lib.rs

@@ -1,8 +1,7 @@
 // This file is part of libfringe, a low-level green threading library.
 // Copyright (c) 2015, edef <edef@edef.eu>
 // See the LICENSE file included in this distribution.
-#![feature(no_std)]
-#![feature(asm, core)]
+#![feature(asm)]
 #![no_std]
 
 //! libfringe is a low-level green threading library.

src/os/mod.rs

@@ -11,7 +11,6 @@ mod sys;
 /// anonymous memory mapping facility, usually `mmap`.
 /// The stack it provides comes with a guard page, which is not included
 /// in the stack limit.
-#[allow(raw_pointer_derive)]
 #[derive(Debug)]
 pub struct Stack {
   ptr: *mut u8,