Add libc++ and libc++abi to third-party.

third_party/libc++/libc++.gyp

+# Copyright (c) 2012 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++',
+      'type': 'shared_library',
+      'variables': {
+         'prune_self_dependency': 1,
+      },
+      'dependencies=': [],
+      'sources': [
+        'src/algorithm.cpp',
+        'src/bind.cpp',
+        'src/chrono.cpp',
+        'src/condition_variable.cpp',
+        'src/debug.cpp',
+        'src/exception.cpp',
+        'src/future.cpp',
+        'src/hash.cpp',
+        'src/ios.cpp',
+        'src/iostream.cpp',
+        'src/locale.cpp',
+        'src/memory.cpp',
+        'src/mutex.cpp',
+        'src/new.cpp',
+        'src/optional.cpp',
+        'src/random.cpp',
+        'src/regex.cpp',
+        'src/shared_mutex.cpp',
+        'src/stdexcept.cpp',
+        'src/string.cpp',
+        'src/strstream.cpp',
+        'src/system_error.cpp',
+        'src/thread.cpp',
+        'src/typeinfo.cpp',
+        'src/utility.cpp',
+        'src/valarray.cpp',
+      ],
+      'include_dirs': [
+        'include',
+        '../libc++abi/include',
+      ],
+      'cflags': [
+        '-g', '-Os', '-fPIC',
+        '-std=c++11',
+        '-fstrict-aliasing',
+        '-Wall', '-Wextra', '-Wshadow', '-Wconversion', '-Wnewline-eof', '-Wpadded',
+        '-Wmissing-prototypes', '-Wstrict-aliasing=2', '-Wstrict-overflow=4',
+        '-nostdinc++',
+      ],
+      'direct_dependent_settings': {
+        'include_dirs': [

[bradn, 2013/12/06 18:11:20]

Rather than have to inject boilerplate into each nacl target. You should be able
to reliably wrap these flags and include_dirs in a target_condition (which will
enable them only in relevant targets):

'target_conditions': [
  ['_type!="none"', {
    includes....
    flags...
  ],
}],

By avoiding the none targets you should be able to avoid injecting flags into
the nacl parts of the build without having to call them out explicitly.
There's a couple of options for the condition, I'm not sure which is ideal:
- _type!="none" (avoid none targets which either don't need the flags or are
nacl targets)
- nacl_untrusted_build==0 (just avoid the nacl targets)

I would lean towards the first, because some nacl targets do not use the
nacl_untrusted_build flag (typically these would have nlib_target!=""). I'm a
little surprised you didn't hit these targets.

+          'include',
+        ],
+        'cflags_cc': [
+          '-nostdinc++',
+        ],
+        'ldflags': [
+          '-stdlib=libc++',
+          '-L<(PRODUCT_DIR)/lib/',
+        ],
+      },
+      'cflags_cc!': [
+        '-fno-rtti',
+      ],
+      'cflags!': [
+        '-fno-exceptions',
+        '-fvisibility=hidden',
+      ],
+      'ldflags': [
+        '-nodefaultlibs',
+      ],
+      'libraries': [
+        '-lrt',
+        '-lc',
+      ],
+    },
+  ]
+}