message: python-setup: flush at the end of `_check_call`
diff: @@ -15,6 +15,8 @@ def _check_call(command, extra_env={}):
  env = os.environ.copy()
  env.update(extra_env)
  subprocess.check_call(command, stdin=subprocess.DEVNULL, env=env)
  + sys.stdout.flush()
  + sys.stderr.flush()
  def _check_output(command, extra_env={}):
  