get rid of some minor warnings

benches/context_new.rs

@@ -4,7 +4,7 @@
 #![feature(test)]
 extern crate test;
 extern crate fringe;
-use fringe::{Context, Stack};
+use fringe::Context;
 
 static mut ctx_slot: *mut Context<'static, SliceStack<'static>> = 0 as *mut Context<_>;
 static mut stack_buf: [u8; 1024] = [0; 1024];

src/arch/x86/mod.rs

@@ -8,7 +8,6 @@ use super::common::{push, rust_trampoline};
 
 pub const STACK_ALIGN: usize = 16;
 
-#[allow(raw_pointer_derive)]
 #[derive(Debug)]
 pub struct Registers {
   esp: *mut usize