message: rename liballoc to realize compatibility to the last version of liballoc
diff: #![allow(dead_code)]
  -use alloc::alloc::{Alloc, AllocErr, Layout};
  -use core::alloc::GlobalAlloc;
  +use core::alloc::{GlobalAlloc, AllocRef, AllocErr, Layout};
  use core::ops::Deref;
  use core::ptr::NonNull;
  use core::{mem, ptr};
  @@ -158,7 +157,7 @@ impl Heap {
  }
  }
  -unsafe impl Alloc for Heap {
  +unsafe impl AllocRef for Heap {
  unsafe fn alloc(&mut self, layout: Layout) -> Result<NonNull<u8>, AllocErr> {
  self.allocate_first_fit(layout)
  }
  