Move libc++ and libc++abi to buildtools.

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

-# Copyright 2013 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',
-      '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_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': [
-        '-fstrict-aliasing',
-        '-nostdinc++',
-        '-std=c++11',
-      ],
-      'cflags_cc!': [
-        '-fno-exceptions',
-        '-fno-rtti',
-      ],
-      'cflags!': [
-        '-fvisibility=hidden',
-      ],
-      'ldflags': [
-        '-nodefaultlibs',
-      ],
-      'ldflags!': [
-        '-pthread',
-      ],
-      'libraries': [
-        '-lc',
-        '-lgcc_s',
-        '-lpthread',
-        '-lrt',
-      ]
-    },
-  ]
-}