Rebased localmods in libcxx to 223109.

include/atomic

 // -*- C++ -*-
 //===--------------------------- atomic -----------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
@@ skipping 797 matching lines @@
     return __y;
 }
 
 // general atomic<T>
 
 template <class _Tp, bool = is_integral<_Tp>::value && !is_same<_Tp, bool>::value>
 struct __atomic_base  // false
 {
     mutable _Atomic(_Tp) __a_;
 
+  // @LOCALMOD-BEGIN The NaCl builtin delays resolution of the lock-free
+  //                 property until translation time (time at which the
+  //                 actual target is known).
+#if defined (__pnacl__)
+    _LIBCPP_INLINE_VISIBILITY
+    bool is_lock_free() const volatile _NOEXCEPT
+        {return __nacl_atomic_is_lock_free(sizeof(_Tp), &__a_);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool is_lock_free() const _NOEXCEPT
+        {return __nacl_atomic_is_lock_free(sizeof(_Tp), &__a_);}
+#else
     _LIBCPP_INLINE_VISIBILITY
     bool is_lock_free() const volatile _NOEXCEPT
         {return __c11_atomic_is_lock_free(sizeof(_Tp));}
     _LIBCPP_INLINE_VISIBILITY
     bool is_lock_free() const _NOEXCEPT
         {return __c11_atomic_is_lock_free(sizeof(_Tp));}
+#endif // @LOCALMOD-END
     _LIBCPP_INLINE_VISIBILITY
     void store(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
         {__c11_atomic_store(&__a_, __d, __m);}
     _LIBCPP_INLINE_VISIBILITY
     void store(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
         {__c11_atomic_store(&__a_, __d, __m);}
     _LIBCPP_INLINE_VISIBILITY
     _Tp load(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
         {return __c11_atomic_load(&__a_, __m);}
     _LIBCPP_INLINE_VISIBILITY
@@ skipping 945 matching lines @@
 #define ATOMIC_LLONG_LOCK_FREE     __GCC_ATOMIC_LLONG_LOCK_FREE
 #define ATOMIC_POINTER_LOCK_FREE   __GCC_ATOMIC_POINTER_LOCK_FREE
 
 #endif  //  !__has_feature(cxx_atomic)
 
 _LIBCPP_END_NAMESPACE_STD
 
 #endif  // !_LIBCPP_HAS_NO_THREADS
 
 #endif  // _LIBCPP_ATOMIC