Add nacl_sdk gyp meta-target.

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 160 matching lines @@
       'dependencies': [
         '<(DEPTH)/native_client/src/shared/platform/platform.gyp:platform',
         '<(DEPTH)/native_client/src/shared/gio/gio.gyp:gio',
       ],
     },
     {
       'target_name': 'platform_lib',
       'type': 'none',
       'variables': {
         'nlib_target': 'libplatform.a',
+        'nso_target': 'libplatform.so',
         'build_glibc': 1,
         'build_newlib': 1,
         'sources': [
           'nacl_check.c',
           'nacl_log.c',
           'posix/condition_variable.c',
           'posix/lock.c',
           'posix/nacl_exit.c',
           'posix/nacl_thread_id.c',
           'posix/nacl_threads.c',
@@ skipping 36 matching lines @@
           ],
           'dependencies': [
             '<(DEPTH)/native_client/src/shared/platform/platform.gyp:platform64',
             '<(DEPTH)/native_client/src/shared/gio/gio.gyp:gio64',
           ],
         },
       ],
     }],
   ],
 }