Add untrusted NaCl build for PPAPI proxy.

ppapi/ppapi_proxy_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.
 
-# This is the "public" ppapi.gyp file, which must have dependencies on the
-# redistributable portions of PPAPI only. This prevents circular dependencies
-# in the .gyp files (since ppapi_internal depends on parts of Chrome).
-
 {
+  'variables': {
+    'chromium_code': 1,
+  },
+  'includes': [
+    '../native_client/build/untrusted.gypi',
+    'ppapi_proxy.gypi',
+  ],
   'conditions': [
-    ['disable_nacl==0 and build_ppapi_ipc_proxy_untrusted==1', {
-      'includes': ['ppapi_proxy_untrusted.gypi'],
+    ['disable_nacl==0 and disable_nacl_untrusted==0', {
+      'targets': [
+        {
+          'target_name': 'ppapi_proxy_untrusted',
+          'type': 'none',
+          'variables': {
+            'ppapi_proxy_target': 1,
+            'nacl_untrusted_build': 1,
+            'nlib_target': 'libppapi_proxy_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',
+            '../ppapi/ppapi_shared_untrusted.gyp:ppapi_shared_untrusted',
+          ],
+        },
+      ],
     }],
   ],
-  'targets': [],
 }