ninja/mac: Don't link c-file-only targets to libstdc++

test/make_global_settings/env-wrapper/gyptest-wrapper.py

 #!/usr/bin/env python
 
 # Copyright (c) 2013 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Verifies *_wrapper in environment.
 """
 
@@ skipping 13 matching lines @@
 os.environ['GYP_CROSSCOMPILE'] = '1'
 test.run_gyp('wrapper.gyp')
 os.environ.clear()
 os.environ.update(old_env)
 
 if test.format == 'ninja':
   cc_expected = ('cc = ' + os.path.join('..', '..', 'distcc') + ' ' +
                  os.path.join('..', '..', 'clang'))
   cc_host_expected = ('cc_host = ' + os.path.join('..', '..', 'ccache') + ' ' +
                       os.path.join('..', '..', 'clang'))
-  ld_expected = 'ld = ../../distlink $cxx'
+  ld_expected = 'ld = ../../distlink $cc'
+  if sys.platform != 'win32':
+    ldxx_expected = 'ldxx = ../../distlink $cxx'
+
   if sys.platform == 'win32':
      ld_expected = 'link.exe'
   test.must_contain('out/Default/build.ninja', cc_expected)
   test.must_contain('out/Default/build.ninja', cc_host_expected)
   test.must_contain('out/Default/build.ninja', ld_expected)
+  if sys.platform != 'win32':
+    test.must_contain('out/Default/build.ninja', ldxx_expected)
 
 test.pass_test()