Sanitizers: Roll in 16 months of libcxx and libcxxabi changes.

third_party/libc++abi/libc++abi.gyp

 # Copyright 2015 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.
 
 {
   'targets': [
     {
       'target_name': 'libc++abi',
       'type': 'static_library',
       'toolsets': ['host', 'target'],
       'dependencies=': [],
       'sources': [
         'trunk/src/abort_message.cpp',
         'trunk/src/cxa_aux_runtime.cpp',
         'trunk/src/cxa_default_handlers.cpp',
         'trunk/src/cxa_demangle.cpp',
         'trunk/src/cxa_exception.cpp',
         'trunk/src/cxa_exception_storage.cpp',
         'trunk/src/cxa_guard.cpp',
         'trunk/src/cxa_handlers.cpp',
         'trunk/src/cxa_new_delete.cpp',
         'trunk/src/cxa_personality.cpp',
+        'trunk/src/cxa_thread_atexit.cpp',
         'trunk/src/cxa_unexpected.cpp',
         'trunk/src/cxa_vector.cpp',
         'trunk/src/cxa_virtual.cpp',
         'trunk/src/exception.cpp',
         'trunk/src/private_typeinfo.cpp',
         'trunk/src/stdexcept.cpp',
         'trunk/src/typeinfo.cpp',
       ],
       'include_dirs': [
         'trunk/include',
         '../libc++/trunk/include'
       ],
       'cflags': [
         '-fPIC',
         '-fstrict-aliasing',
         '-nostdinc++',
         '-pthread',
         '-std=c++11',
       ],
       'cflags_cc!': [
         '-fno-exceptions',
         '-fno-rtti',
       ],
       'cflags!': [
         '-fvisibility=hidden',
       ],
     },
   ]
 }