[clang] Add clang atomic control options and attribute (PR #114841)

[Erich Keane via cfe-commits]

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@@ -0,0 +1,19 @@
+//===--- AtomicOptions.def - Atomic Options database -------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// This file defines the Atomic language options. Users of this file
+// must define the OPTION macro to make use of this information.
+#ifndef OPTION
----------------
erichkeane wrote:

```suggestion
#ifndef ATOMIC_OPTION
```

https://github.com/llvm/llvm-project/pull/114841