It is not optimal to test sys.stderr on a debug build.

Lib/test/test_sysconfig.py

@@ -245,8 +245,7 @@ class TestSysConfig(unittest.TestCase):
         def get(python):
             cmd = [python, '-c',
                    'import sysconfig; print sysconfig.get_platform()']
-            p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
-                                      stderr=subprocess.PIPE)
+            p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
             return p.communicate()
         real = os.path.realpath(sys.executable)
         link = os.path.abspath(TESTFN)