Add nacl_sdk gyp meta-target.

src/trusted/weak_ref/weak_ref.gyp

 # -*- python -*-
 # Copyright 2011 (c) 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.
 {
   'includes': [
     '../../../build/common.gypi',
   ],
   'target_defaults': {
     'variables':{
@@ skipping 16 matching lines @@
   },
   'conditions': [
     # NOTE: We do not support untrusted gyp build on arm yet.
     ['target_arch!="arm"', {
       'targets': [
         {
           'target_name': 'weak_ref_lib',
           'type': 'none',
           'variables': {
             'nlib_target': 'libweak_ref.a',
+            'nso_target': 'libweak_ref.so',
             'build_glibc': 1,
             'build_newlib': 1,
             'sources': ['weak_ref.cc'],
           },
           'dependencies': [
             '<(DEPTH)/native_client/tools.gyp:prep_toolchain',
           ],
         },
       ],
     }],
@@ skipping 19 matching lines @@
       'type': 'static_library', # 'dynamic_library', ?!?
       'variables': {
         'target_base': 'weak_ref',
       },
       'dependencies': [
         '<(DEPTH)/native_client/src/shared/platform/platform.gyp:platform',
       ],
     },
   ],
 }