iwyu: Cleanup in the following files:

base/atomicops.h

-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // For atomic operations on reference counts, see atomic_refcount.h.
 // For atomic operations on sequence numbers, see atomic_sequence_num.h.
 
 // The routines exported by this module are subtle.  If you use them, even if
 // you get the code right, it will depend on careful reasoning about atomicity
 // and memory ordering; it will be less readable, and harder to maintain.  If
 // you plan to use these routines, you should have a good reason, such as solid
@@ skipping 11 matching lines @@
 //   NoBarrier_Load()
 // Although there are currently no compiler enforcement, you are encouraged
 // to use these.
 //
 
 #ifndef BASE_ATOMICOPS_H_
 #define BASE_ATOMICOPS_H_
 #pragma once
 
 #include "base/basictypes.h"
-#include "base/port.h"
+#include "build/build_config.h"
 
 namespace base {
 namespace subtle {
 
 // Bug 1308991.  We need this for /Wp64, to mark it safe for AtomicWord casting.
 #ifndef OS_WIN
 #define __w64
 #endif
 typedef __w64 int32 Atomic32;
 #ifdef ARCH_CPU_64_BITS
@@ skipping 95 matching lines @@
 #include "base/atomicops_internals_x86_macosx.h"
 #elif defined(COMPILER_GCC) && defined(ARCH_CPU_X86_FAMILY)
 #include "base/atomicops_internals_x86_gcc.h"
 #elif defined(COMPILER_GCC) && defined(ARCH_CPU_ARM_FAMILY)
 #include "base/atomicops_internals_arm_gcc.h"
 #else
 #error "Atomic operations are not supported on your platform"
 #endif
 
 #endif  // BASE_ATOMICOPS_H_