Make header include guards great again

runtime/vm/atomic_macos.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-#ifndef VM_ATOMIC_MACOS_H_
-#define VM_ATOMIC_MACOS_H_
+#ifndef RUNTIME_VM_ATOMIC_MACOS_H_
+#define RUNTIME_VM_ATOMIC_MACOS_H_
 
-#if !defined VM_ATOMIC_H_
+#if !defined RUNTIME_VM_ATOMIC_H_
 #error Do not include atomic_macos.h directly. Use atomic.h instead.
 #endif
 
 #if !defined(TARGET_OS_MACOS)
 #error This file should only be included on Mac OS X builds.
 #endif
 
 namespace dart {
 
 
@@ skipping 42 matching lines @@
 
 inline uint32_t AtomicOperations::CompareAndSwapUint32(uint32_t* ptr,
                                                        uint32_t old_value,
                                                        uint32_t new_value) {
   return __sync_val_compare_and_swap(ptr, old_value, new_value);
 }
 #endif  // !defined(USING_SIMULATOR_ATOMICS)
 
 }  // namespace dart
 
-#endif  // VM_ATOMIC_MACOS_H_
+#endif  // RUNTIME_VM_ATOMIC_MACOS_H_