Three patches from issue #1047, by Amaury Forgeot d'Arc:

1/ getargs.diff adds the 'Z' and 'Z#' format specifiers for
PyArg_ParseTuple. They mimic z and z# for unicode strings, by accepting
a Unicode or None (in which case the Py_UNICODE* pointer is set to
NULL). With doc and tests.

2/ subprocess.diff converts file PC/_subprocess.c to unicode. We use the
Unicode version of the win32 api (and Z conversion from previous patch)

3/ stdout.diff: sys.stdout must not convert the line endings, Windows
already does it.
Without this patch, when redirecting the output of python, the file
contains \r\r\n for each line. (test_subprocess did catch this)

However, I (GvR) removed the change to _fileio.c (included in the
patches) that prevents closing file descripors < 3 from being closed;
I think that needs to be solved in a different way.

Doc/c-api/utilities.rst

@@ -484,6 +484,13 @@ variable(s) whose address should be passed.
    by interpreting their read-buffer pointer as pointer to a :ctype:`Py_UNICODE`
    array.
 
+``Z`` (Unicode or ``None``) [Py_UNICODE \*]
+   Like ``s``, but the Python object may also be ``None``, in which case the C
+   pointer is set to *NULL*.
+
+``Z#`` (Unicode or ``None``) [Py_UNICODE \*, int]
+   This is to ``u#`` as ``Z`` is to ``u``.
+
 ``es`` (string, Unicode object or character buffer compatible object) [const char \*encoding, char \*\*buffer]
    This variant on ``s`` is used for encoding Unicode and objects convertible to
    Unicode into a character buffer. It only works for encoded data without embedded