Issue #26516:

* Add PYTHONMALLOC environment variable to set the Python memory
  allocators and/or install debug hooks.
* PyMem_SetupDebugHooks() can now also be used on Python compiled in release
  mode.
* The PYTHONMALLOCSTATS environment variable can now also be used on Python
  compiled in release mode. It now has no effect if set to an empty string.
* In debug mode, debug hooks are now also installed on Python memory allocators
  when Python is configured without pymalloc.

in BaseHTTPRequestHandler

Initial patch by karlcow.

#25687: clarify that errors in tearDown increase the total number of reported errors.  Initial patch by HyeSoo Park.

Tamás Bence Gedai.

Tamás Bence Gedai.

Revert:
"Always test datetime.strftime("%4Y")

Issue #13305: Always test datetime.datetime.strftime("%4Y") for years < 1900."

In fact, strftime("%4Y") fails on most platforms.

Issue #13305: Always test datetime.datetime.strftime("%4Y") for years < 1900.

Patch by Dmitry Shachnev.

Issue #26323: Add assert_called() and assert_called_once() methods to
unittest.mock.Mock.

Patch by Dmitry Shachnev.

NotImplementedError instead of ImportError.

NotImplementedError instead of ImportError.

multipliers, not final sizes.  Explain y default for .zoom and .subsample.
Initial patch by Serhiy Storchaka.

* add link to PYTHONMALLOCSTATS env var
* add parameters to PyMem macros like PyMem_MALLOC()
* fix PyMem_SetupDebugHooks(): add Calloc functions
* add some newlines for readability

Patch by Tamás Bence Gedai.

Added few missed tests for configure options.