Make chrome_browser_tests work with irt=0 again

tests/plugin_async_messaging/nacl.scons

 # -*- python -*-
 # Copyright (c) 2011 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.
 
 Import('env')
 
 dest_copy = env.Replicate('${STAGING_DIR}', 'async_messaging.html')
 env.Replicate('${STAGING_DIR}',
               '${SCONSTRUCT_DIR}/tools/browser_tester/browserdata/nacltest.js')
 
 async_nexe_name = 'async_message_test_%s' % env.get('TARGET_FULLARCH')
 async_message_prog = env.ComponentProgram(
     async_nexe_name, 'async_message_test.c',
     EXTRA_LIBS=['${NON_PPAPI_BROWSER_LIBS}',
-                'srpc', 'platform', 'gio', 'imc', 'imc_syscalls', 'pthread'
+                'srpc', 'platform', 'gio', 'imc', 'imc_syscalls',
+                '${PTHREAD_LIBS}',
                 ])
 
 test_files = [
     env.File('${STAGING_DIR}/nacltest.js'),
     env.File('${STAGING_DIR}/%s${PROGSUFFIX}' % async_nexe_name),
     ]
 # These are not true dependencies: They are not needed for the .html
 # file to be replicated to "staging", but they are needed for the
 # .html file to work when run.
 # TODO(mseaborn): Similar logic is duplicated in
 # tests/inbrowser_test_runner/nacl.scons.  Reduce the duplication.
 env.Depends(dest_copy, test_files)
 env.Alias('async_messaging.html', dest_copy)
 
 node = env.PPAPIBrowserTester(
     'async_messaging_chrome_browser_test.out',
     url='async_messaging.html',
     files=[env.File('async_messaging.html'),
            env.File('async_message_test.nmf')] + test_files,
     args=['--enable_experimental_js'])
 
 env.AddNodeToTestSuite(node,
                        ['chrome_browser_tests'],
                        'run_async_messaging_test',
                        is_broken=env.PPAPIBrowserTesterIsBroken())