Issue #26058: Add a new private version to the builtin dict type, incremented
at each dictionary creation and at each dictionary change.

Implementation of the PEP 509.

Issue #21201: Improves readability of multiprocessing error message from server to client for certain exceptions

Issue #21201: Improves readability of multiprocessing error message from server to client for certain exceptions

Patch by Emanuel Barry, reviewed by Serhiy Storchaka and Martin Panter.

Issue #27350.

Issue #27350.

Issue #27350.

Issue #27350.

Issue #27350.

And most of the tools.

Patch by Emanual Barry, reviewed by me, Serhiy Storchaka, and
Martin Panter.

Patch by Claude Paroz.

Issue #27350: use Py_MEMBER_SIZE() macro to get the size of
PyDictKeyEntry.dk_indices, rather than hardcoding 8.

Initial patch contributed by Denver Coneybeare.

Issue #27350: `dict` implementation is changed like PyPy. It is more compact
and preserves insertion order.

_PyDict_Dummy() function has been removed.

Disable test_gdb: python-gdb.py is not updated yet to the new structure of
compact dictionaries (issue #28023).

Patch written by INADA Naoki.