Compile and link libcrypto_nacl for nacl targets.

crypto/crypto_nacl.gyp

 # Copyright 2014 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',
     'crypto.gypi',
   ],
   'targets': [
     {
       'target_name': 'crypto_nacl',
       'type': 'none',
       'variables': {
         'nacl_untrusted_build': 1,
         'nlib_target': 'libcrypto_nacl.a',
         'build_glibc': 0,
         'build_newlib': 0,
         'build_pnacl_newlib': 1,
+        'build_irt': 1,
       },
       'dependencies': [
         '../third_party/boringssl/boringssl_nacl.gyp:boringssl_nacl',
         '../native_client_sdk/native_client_sdk_untrusted.gyp:nacl_io_untrusted',
       ],
       'defines': [
         'CRYPTO_IMPLEMENTATION',
       ],
       'sources': [
         '<@(crypto_sources)',
       ],
       'sources/': [
         ['exclude', '_nss\.(cc|h)$'],
         ['exclude', '^(mock_)?apple_'],
         ['exclude', '^capi_'],
         ['exclude', '^cssm_'],
         ['exclude', '^nss_'],
         ['exclude', '^mac_'],
         ['exclude', '^third_party/nss/'],
         ['include', '^third_party/nss/sha512.cc'],
       ],
     },
   ],
 }