Patch by Eryk Sun.

Not completely mechanical since support for East Asian Width changes—emoji
codepoints became Wide—had to be added to unicodedata.

Patch by Ed Schouten.

Issue #28127: Add a function to check that a dictionary remains consistent
after any change.

By default, tables are not checked, only basic attributes. Define DEBUG_PYDICT
(ex: gcc -D DEBUG_PYDICT) to also check dictionary "content".

Backport of 01ddd608b85c.

zipimport should use the same optimization level as the interpreter.

Issue #28188: Use PyMem_Calloc() to get rid of a type-limits warning and an extra memset() call in _ssl.c.

Issue #28120: Fix dict.pop() for splitted dictionary when trying to remove a
"pending key" (Not yet inserted in split-table).

Patch by Xiang Zhang.

A newer instance of this option, enabled in the configure script when
building outside the source tree, made this redundant.

find_empty_slot() only supports combined dict