Build gtest for both 'host' and 'target'.

testing/gtest.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': 'gtest',
+      'toolsets': ['host', 'target'],
       'type': 'static_library',
       'sources': [
         'gtest/include/gtest/gtest-death-test.h',
         'gtest/include/gtest/gtest-message.h',
         'gtest/include/gtest/gtest-param-test.h',
         'gtest/include/gtest/gtest-printers.h',
         'gtest/include/gtest/gtest-spi.h',
         'gtest/include/gtest/gtest-test-part.h',
         'gtest/include/gtest/gtest-typed-test.h',
         'gtest/include/gtest/gtest.h',
@@ skipping 208 matching lines @@
     {
       'target_name': 'gtest_prod',
       'toolsets': ['host', 'target'],
       'type': 'none',
       'sources': [
         'gtest/include/gtest/gtest_prod.h',
       ],
     },
   ],
 }