Add untrusted NaCl build for PPAPI proxy.

ppapi/ppapi_shared_untrusted.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.
+
+{
+  'variables': {
+    'chromium_code': 1,
+  },
+  'includes': [
+    '../native_client/build/untrusted.gypi',
+    'ppapi_shared.gypi',
+  ],
+  'conditions': [
+    ['disable_nacl==0 and disable_nacl_untrusted==0', {
+      'targets': [
+        {
+          'target_name': 'ppapi_shared_untrusted',
+          'type': 'none',
+          'variables': {
+            'ppapi_shared_target': 1,
+            'nacl_untrusted_build': 1,
+            'nlib_target': 'libppapi_shared_untrusted.a',
+            'build_glibc': 0,
+            'build_newlib': 1,
+          },
+          'dependencies': [
+            '<(DEPTH)/native_client/tools.gyp:prep_toolchain',
+            '../base/base_untrusted.gyp:base_untrusted',
+            '../ipc/ipc_untrusted.gyp:ipc_untrusted',
+          ],
+        },
+      ],
+    }],
+  ],
+}