The documentation for CERT_NONE, CERT_OPTIONAL, and CERT_REQUIRED were
misleading and partly wrong. It fails to explain that OpenSSL behaves
differently in client and server mode. Also OpenSSL does validate the
cert chain everytime. With SSL_VERIFY_NONE a validation error is not
fatal in client mode and does not request a client cert in server mode.
Also discourage people from using CERT_OPTIONAL in client mode.

Change suggested by Eryk Sun in a comment on PR 7137 after it was merged.

This is a separate PR because this does not backport to 3.6.

On Windows 8.1+ or 10, with DPI compatibility properties of the Python binary
unchanged, and a monitor resolution greater than 96 DPI, this should
make text and lines sharper. It should otherwise have no effect.

Using a magnifier, I determined that the improvement comes from horizontal and
lines being better lined up with the monitor pixels. I checked that this call causes
no problem on any Windows buildbot, including the Win7 buildbots. Unlike most
IDLE patches, this one can be easily reverted by users by removing a few lines,
at the top of idlelib/pyshell.py.

The docs claimed that a list of EmailMessage objects could be
passed to set_content(), but this was never implemented.

* Add declarations even if they are overridden by macros.
* Make the declaration and the definition of PyExceptionClass_Name
  consistent.

Before Python 3.6, os.path.abspath(None) used to report an AttributeError which was properly caught inside site.abs_paths, making it ignore __main__, one of sys.modules, which has __file__ and __cached__ set to None. With 3.6, os.path.abspath(None) raises TypeError instead which site.abs_path was not expecting.  This resulted in an uncaught exception if a user had PYTHONSTARTUP set and the application called site.main() which a number of third-party programs do.

A datetime object d is aware if d.tzinfo is not None and
d.tzinfo.utcoffset(d) does  not return None. If d.tzinfo is None,
or if d.tzinfo is not None but d.tzinfo.utcoffset(d) returns None,
 d is naive.

This commit ensures that instances with non-None d.tzinfo, but
d.tzinfo.utcoffset(d) returning None are treated as naive.

In addition, C acceleration code will raise TypeError if
d.tzinfo.utcoffset(d) returns an object with the type other than
timedelta.

* Updated the documentation.

Assume that the term "naive" is defined elsewhere and remove the
not entirely correct clarification.  Thanks, Tim.

Users can now click on context lines.

This call became unneeded after the posix module was converted to the
Argument Clinic in 2f93635d and should
have been removed as part of that change.

Seems they were added by double applying blurb.

This is a fixup to 19a44f63

During development of the limited API support for PySide,
we saw an error in a macro that accessed a type field.

This patch fixes the 7 errors in the Python headers.
Macros which were not written as capitals were implemented
as function.

To do the necessary analysis again, a script was included that
parses all headers and looks for "->tp_" in serctions which can
be reached with active limited API.

It is easily possible to call this script as a test.

Error listing:

../../Include/objimpl.h:243
#define PyObject_IS_GC(o) (PyType_IS_GC(Py_TYPE(o)) && \
    (Py_TYPE(o)->tp_is_gc == NULL || Py_TYPE(o)->tp_is_gc(o)))
Action: commented only

../../Include/objimpl.h:362
#define PyType_SUPPORTS_WEAKREFS(t) ((t)->tp_weaklistoffset > 0)
Action: commented only

../../Include/objimpl.h:364
#define PyObject_GET_WEAKREFS_LISTPTR(o) \
    ((PyObject **) (((char *) (o)) + Py_TYPE(o)->tp_weaklistoffset))
Action: commented only

../../Include/pyerrors.h:143
#define PyExceptionClass_Name(x) \
     ((char *)(((PyTypeObject*)(x))->tp_name))
Action: implemented function

../../Include/abstract.h:593
#define PyIter_Check(obj) \
    ((obj)->ob_type->tp_iternext != NULL && \
     (obj)->ob_type->tp_iternext != &_PyObject_NextNotImplemented)
Action: implemented function

../../Include/abstract.h:713
#define PyIndex_Check(obj)                              \
    ((obj)->ob_type->tp_as_number != NULL &&            \
     (obj)->ob_type->tp_as_number->nb_index != NULL)
Action: implemented function

../../Include/abstract.h:924
#define PySequence_ITEM(o, i)\
    ( Py_TYPE(o)->tp_as_sequence->sq_item(o, i) )
Action: commented only

_Py_IDENTIFIER(argv) is now unused.

While locale coercion and UTF-8 mode turned out to
be complementary ideas rather than competing ones,
it isn't immediately obvious why it's useful to
have both, or how they interact at runtime.

This updates both the Python 3.7 What's New doc
and the PYTHONCOERCECLOCALE and PYTHONUTF8
documentation in an attempt to clarify that
relationship:

- in the respective What's New sections, add a closing paragraph
  explaining which problem each one solves, and pointing to the
  other PEP's section for the specific aspects it relies on the other
  PEP to solve
- use "locale-aware mode" as a more descriptive term for the
  default non-UTF-8 mode
- improve wording conistenccy between the PYTHONCOERCECLOCALE
  and PYTHONUTF8 docs when they cover the same thing (mostly
  related to legacy locale detection and setting the standard
  stream error handler)
- improve the description of the locale coercion trigger conditions
  (including pointing out that setting LC_ALL turns off locale coercion)
- port the full description of the UTF-8 mode behaviour changes
  from PEP 540 into the PYTHONUTF8 documentation
- be explicit that PYTHONIOENCODING still overrides the settings
  for the standard streams
- mention concrete examples of things that do and don't get their
  text encoding assumptions adjusted by the two text encoding
  assumption override techniques

Since implementation of bpo-25283, the objects returned by time.localtime
always have tm_zone and tm_gmtoff attributes.  Remove code that
anticipates their absence.

* Added a test case for strftime("%z").

The added test checks a case with UTC offest expressed in an integer
number of seconds.

* Added a test comparing naive and aware datetimes.

Check that a greater than  comparison of a naive  datetime instance with
an aware one raises a TypeError.

* Test datetime in fold or in gap comparison both ways.

Supersedes https://github.com/python/cpython/pull/2490

More consistent with how other parts of Python find the filename (e.g. tracebacks and pdb).