Unfortunately, this change has broken windows support of the subprocess
module, which now reports, on "import subprocess".

>>> import subprocess
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\loewis\31\python\lib\subprocess.py", line 390, in <module>
    _PIPE_BUF = getattr(select, 'PIPE_BUF', 512)
NameError: name 'select' is not defined

As a consequence, even building Python on Windows now fails, so setting
the priority to "release blocker". One solution would be to move the
"import select" to being top-level.