* Add timezone to datetime C API

* Add documentation for timezone C API macros

* Add dedicated tests for datetime type check macros

* Remove superfluous C API test

* Drop support for TimeZoneType in datetime C API

* Expose UTC singleton to the datetime C API

* Update datetime C-API documentation to include links

* Add reference count information for timezone constructors

To support reproducible builds, the setting of of SOURCE_DATE_EPOCH triggers the py_compile module -- and by extension, compileall -- to forcibly compile with hash-based .pyc files. This eliminates the possibility of timestamp-based .pyc files which vary between builds.

* Rename sock_sendfile test methods
* Make sock_sendfile tests more stable

* bpo-32651 - In the documentation for os.getlogin(), recommend getpass.getuser()

Specifically, it's not possible to subclass Task/Future classes
and override the following methods:

* Future._schedule_callbacks
* Task._step
* Task._wakeup

_PyCoreConfig_Read() is now responsible to compute sys.path.
So sys.path is now computed before calling _Py_InitializeCore().

Changes:

* Add module_search_path, module_search_paths, executable, prefix,
  base_prefix, exec_prefix and base_exec_prefix to _PyCoreConfig.
* _PyMainInterpreterConfig_Read() now only converts wchar_t** lists
  into a Python list, it doesn't compute sys.path anymore.

Makefile $MACHDEPPATH uses $PLATDIR, but this variable was removed.
So remove also $MACHDEPPATH.

Remove also $EXTRAMACHDEPPATH.

glibc is deprecating libcrypt in favor of libxcrypt, however python assumes
that crypt.h will always be included. This change makes the header inclusion
explicit when libxcrypt is present on the system.

* bpo-32618: Fix test_mutatingdecodehandler not testing test.mutating

It should test both test.replacing and test.mutating instead of test test.replacing twice.

"python3 -bb -Wd" now works as expected:
"python3 -bb -Wd -Werror::BytesWarning" is no more needed.

Update configure since configure.ac was modified to drop support for
FreeBSD 4.

PyUnicode_DecodeLocaleAndSize(), PyUnicode_DecodeLocale() and
PyUnicode_EncodeLocale() now use always use the UTF-8 encoding on
Android, instead of the current locale encoding.

On Android API 19, mbstowcs() and wcstombs() are broken and cannot be
used.

Drop support of FreeBSD 9 and older.

* bpo-31801:  Enum:  add _ignore_ as class option

_ignore_ is a list, or white-space seperated str, of names that will not
be candidates for members; these names, and _ignore_ itself, are removed
from the final class.

* bpo-31801:  Enum:  add documentation for _ignore_

* bpo-31801: Enum: remove trailing whitespace

* bpo-31801: Enum: fix bulleted list format

* bpo-31801: add version added for _ignore_

The previous version was correct in terms of behaviour, but
checking the return value of PyErr_WarnFormat allows to
avoid calling PyErr_Occurred and silences the coverity alarm.

* Add coro.cr_origin and sys.set_coroutine_origin_tracking_depth
* Use coroutine origin information in the unawaited coroutine warning
* Stop using set_coroutine_wrapper in asyncio debug mode
* In BaseEventLoop.set_debug, enable debugging in the correct thread

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.