stabilize atomics (now atomic)

This commit stabilizes the `std::sync::atomics` module, renaming it to
`std::sync::atomic` to match library precedent elsewhere, and tightening
up behavior around incorrect memory ordering annotations.

The vast majority of the module is now `stable`. However, the
`AtomicOption` type has been deprecated, since it is essentially unused
and is not truly a primitive atomic type. It will eventually be replaced
by a higher-level abstraction like MVars.

Due to deprecations, this is a:

[breaking-change]

2 files changed, 4 insertions, 4 deletions

diff --git a/src/libstd/io/tempfile.rs b/src/libstd/io/tempfile.rs
index f580dfd80f0..1d53ed81437 100644
--- a/src/libstd/io/tempfile.rs
+++ b/src/libstd/io/tempfile.rs
@@ -19,7 +19,7 @@ use option::{Option, None, Some};
 use os;
 use path::{Path, GenericPath};
 use result::{Ok, Err};
-use sync::atomics;
+use sync::atomic;
 
 #[cfg(stage0)]
 use iter::Iterator; // NOTE(stage0): Remove after snapshot.
@@ -42,13 +42,13 @@ impl TempDir {
             return TempDir::new_in(&os::make_absolute(tmpdir), suffix);
         }
 
-        static mut CNT: atomics::AtomicUint = atomics::INIT_ATOMIC_UINT;
+        static mut CNT: atomic::AtomicUint = atomic::INIT_ATOMIC_UINT;
 
         for _ in range(0u, 1000) {
             let filename =
                 format!("rs-{}-{}-{}",
                         unsafe { libc::getpid() },
-                        unsafe { CNT.fetch_add(1, atomics::SeqCst) },
+                        unsafe { CNT.fetch_add(1, atomic::SeqCst) },
                         suffix);
             let p = tmpdir.join(filename);
             match fs::mkdir(&p, io::UserRWX) {
diff --git a/src/libstd/io/test.rs b/src/libstd/io/test.rs
index 26e854d9d99..331cfa1a59e 100644
--- a/src/libstd/io/test.rs
+++ b/src/libstd/io/test.rs
@@ -16,7 +16,7 @@ use libc;
 use os;
 use prelude::*;
 use std::io::net::ip::*;
-use sync::atomics::{AtomicUint, INIT_ATOMIC_UINT, Relaxed};
+use sync::atomic::{AtomicUint, INIT_ATOMIC_UINT, Relaxed};
 
 macro_rules! iotest (
     { fn $name:ident() $b:block $(#[$a:meta])* } => (