The constant values of future flags in the __future__ module
is updated in order to prevent collision with compiler flags.
Previously PyCF_ALLOW_TOP_LEVEL_AWAIT was clashing
with CO_FUTURE_DIVISION..
(cherry picked from commit 4454057269b995341b04d13f0bf97f96080f27d0)

Co-authored-by: Batuhan Taşkaya <batuhanosmantaskaya@gmail.com>

Add PyCode_NewEx to be used internally and set PyCode_New as a compatibility wrapper
(cherry picked from commit 4a2edc34a405150d0b23ecfdcb401e7cf59f4650)

Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>

This patch implements per opcode cache mechanism, and use it in
only LOAD_GLOBAL opcode.

Based on Yury's opcache3.patch in bpo-26219.

This commit contains the implementation of PEP570: Python positional-only parameters.

* Update Grammar/Grammar with new typedarglist and varargslist

* Regenerate grammar files

* Update and regenerate AST related files

* Update code object

* Update marshal.c

* Update compiler and symtable

* Regenerate importlib files

* Update callable objects

* Implement positional-only args logic in ceval.c

* Regenerate frozen data

* Update standard library to account for positional-only args

* Add test file for positional-only args

* Update other test files to account for positional-only args

* Add News entry

* Update inspect module and related tests

* Document `from __future__ import annotations`
* Provide plumbing and tests for `from __future__ import annotations`
* Implement unparsing the AST back to string form

This is required for PEP 563 and as such only implements a part of the
unparsing process that covers expressions.

collections.namedtuple() now supports tuples with more than 255 elements.