Adds tls_edit utility which patches irt_core.nexe's TLS usage.

src/shared/platform/platform.gyp

 # -*- python -*-
 #
 # Copyright (c) 2012 The Native Client 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': {
     'common_sources': [
       'nacl_check.c',
@@ skipping 116 matching lines @@
           ]]
         }
       ]
     ],
   },
   'targets': [
     # ----------------------------------------------------------------------
     {
       'target_name': 'platform',
       'type': 'static_library',
+      # tls_edit relies on this which is always built for the host platform.
+      'toolsets': ['host', 'target'],
       'variables': {
         'target_base': 'platform_lib',
       },
       'dependencies': [
         '<(DEPTH)/native_client/src/shared/gio/gio.gyp:gio',
       ],
     },
     # ----------------------------------------------------------------------
     {
       'target_name': 'platform_tests',
@@ skipping 63 matching lines @@
           ],
           'dependencies': [
             '<(DEPTH)/native_client/src/shared/platform/platform.gyp:platform64',
             '<(DEPTH)/native_client/src/shared/gio/gio.gyp:gio64',
           ],
         },
       ],
     }],
   ],
 }