Add an untrusted NaCl build target for jsoncpp.

third_party/jsoncpp/jsoncpp_untrusted.gyp

+# Copyright (c) 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.
+
+{
+  'includes': [
+    '../../build/common_untrusted.gypi',
+    'jsoncpp.gypi',
+  ],
+  'conditions': [
+    ['disable_nacl==0 and disable_nacl_untrusted==0', {
+      'targets': [
+        {
+          'target_name': 'jsoncpp_untrusted',
+          'type': 'none',
+          'variables': {
+            'nacl_untrusted_build': 1,
+            'nlib_target': 'libjsoncpp_untrusted.a',
+            'build_newlib': 1,
+          },
+          'gcc_compile_flags': [
+            # Turn off optimizations based on strict aliasing
+            # because of the workaround at
+            # overrides/src/lib_json/json_value.cpp:38.
+            '-fno-strict-aliasing',
+          ],
+          'dependencies': [
+            '<(DEPTH)/native_client/tools.gyp:prep_toolchain',
+          ],
+        },
+      ],
+    }],
+  ],
+}