Add test certs and test for ECDSA cert and EC/RSA dual mode.

I'm also adding certs for IDNA 2003/2008 tests and simplify some test
data handling.
Signed-off-by: Christian Heimes <christian@python.org>

Add https://www.gnu.org/software/autoconf-archive/ax_check_openssl.html
to auto-detect compiler flags, linker flags and libraries to compile
OpenSSL extensions. The M4 macro uses pkg-config and falls back to
manual detection.

Add autoconf magic to detect usable X509_VERIFY_PARAM_set1_host()
and related functions.

Refactor setup.py to use new config vars to compile _ssl and _hashlib
modules.
Signed-off-by: Christian Heimes <christian@python.org>

This PR re-designs the internal typing API using the new PEP 560 features.
However, there are only few minor changes in the public API.

The suggested replacement for print statements previously failed to account
for leading whitespace and hence could end up including unwanted text in
the proposed call to the print builtin.

Patch by Sanyam Khurana.

Fixes some redirection links in docs.

* Use wider types (int => Py_ssize_t) to avoid integer overflows.
* Fix gc.get_freeze_count(): use Py_ssize_t type rather than int, since gc_list_size() returns a Py_ssize_t.

Where a queue may be invoked from a weakref callback, we need
to use the reentrant SimpleQueue.

The comment for PyThread_allocate_lock says "It has too be implemented ...".
There was an extra "o" in ".. to be implemented.."

This test doesn't care about order, the underlying filesystem APIs do not
guarantee directory listings on subsequent calls will be in the same order.

Use the binary.file instead of utf-8.file to avoid issues with
Unix newlines vs Windows newlines.

bpo-32248: Make sure that Git checks out data files with Unix line
ending on Windows as well.

Use an improved version of multissl test helper to compile a local copy
of OpenSSL 1.1.0g.
Signed-off-by: Christian Heimes <christian@python.org>

* Add tests for date subclass alternate constructors

* Switch over alternate date constructors to fast path

* Switch datetime constructors to fastpath, fix bpo-32404

* Add fast path for datetime in date subclass constructor

* Set fold in constructor in datetime.combine

* Add news entries.

bpo-29240: On FreeBSD, if the LC_CTYPE locale is "C" or "POSIX",
writing and reading non-ASCII bytes into/from a TTY works,
but readline or ncurses ignores non-ASCII bytes on read.

AttributeError was raised always when attribute is not found.
This commit skip raising AttributeError when `tp_getattro` is `PyObject_GenericGetAttr`.
It makes hasattr() and getattr() about 4x faster when attribute is not found.

Add a queue.SimpleQueue class, an unbounded FIFO queue with a reentrant C implementation of put().

* Add _Py_GetLocaleconvNumeric() function: decode decimal_point and
  thousands_sep fields of localeconv() from the LC_NUMERIC encoding,
  rather than decoding from the LC_CTYPE encoding.
* Modify locale.localeconv() and "n" formatter of str.format() (for
  int, float and complex to use _Py_GetLocaleconvNumeric()
  internally.

Modify locale.localeconv(), time.tzname, os.strerror() and other
functions to ignore the UTF-8 Mode: always use the current locale
encoding.

Changes:

* Add _Py_DecodeLocaleEx() and _Py_EncodeLocaleEx(). On decoding or
  encoding error, they return the position of the error and an error
  message which are used to raise Unicode errors in
  PyUnicode_DecodeLocale() and PyUnicode_EncodeLocale().
* Replace _Py_DecodeCurrentLocale() with _Py_DecodeLocaleEx().
* PyUnicode_DecodeLocale() now uses _Py_DecodeLocaleEx() for all
  cases, especially for the strict error handler.
* Add _Py_DecodeUTF8Ex(): return more information on decoding error
  and supports the strict error handler.
* Rename _Py_EncodeUTF8_surrogateescape() to _Py_EncodeUTF8Ex().
* Replace _Py_EncodeCurrentLocale() with _Py_EncodeLocaleEx().
* Ignore the UTF-8 mode to encode/decode localeconv(), strerror()
  and time zone name.
* Remove PyUnicode_DecodeLocale(), PyUnicode_DecodeLocaleAndSize()
  and PyUnicode_EncodeLocale() now ignore the UTF-8 mode: always use
  the "current" locale.
* Remove _PyUnicode_DecodeCurrentLocale(),
  _PyUnicode_DecodeCurrentLocaleAndSize() and
  _PyUnicode_EncodeCurrentLocale().

Clarify that on Windows, path must be a directory.
On Unix, path can be a file or a directory.

`os.path.is*()` can return False if the file can't be accessed.
The behaviour is documented in details in `os.path.exists()`.
Link to `os.path.exists()` from `os.path.is*()`.

The code example that demonstrate how to use enum.Flag was missing
the import of enum.auto.

PyMemoryView_FromMemory() created a memoryview referring to
the internal data of the string.  When the string is destroyed
the memoryview become referring to a freed memory.

glibc has removed Sun RPC. Use replacement libtirpc headers and library in
nis module
Signed-off-by: Christian Heimes <christian@python.org>

In lexical analysis reference documentation, the internal link to
the string literal concatenation section was written as`.. _string-catenation:`.
Changed that to `.. _string-concatenation:`.