gh-144490: Fix test_cppext on Windows

[vstinner]

Don't include pycore_backoff.h and pycore_cell.h on Windows, since they emit C++ compiler warnings.

• Issue: Enhancement request: make pycore_cell.h compile cleanly under C++ #144490

[vstinner]

On Windows with Python built in debug mode, TestInteralCAPI of test_cppext fails the following warnings:

include\internal\mimalloc/mimalloc/types.h(509): error C2220: the following warning is treated as an error
include\internal\mimalloc/mimalloc/types.h(509): warning C4324: 'mi_abandoned_pool_s': structure was padded due to alignment specifier
include\internal\mimalloc/mimalloc/types.h(512): warning C4324: 'mi_abandoned_pool_s': structure was padded due to alignment specifier
include\internal\mimalloc/mimalloc/types.h(513): warning C4324: 'mi_abandoned_pool_s': structure was padded due to alignment specifier
include\internal\mimalloc/mimalloc/types.h(518): warning C4324: 'mi_abandoned_pool_s': structure was padded due to alignment specifier
include\internal\pycore_qsbr.h(75): warning C4200: nonstandard extension used: zero-sized array in struct/union
include\internal\pycore_qsbr.h(75): note: This member will be ignored by a defaulted constructor or copy/move assignment operator
include\internal\pycore_uop.h(26): warning C4201: nonstandard extension used: nameless struct/union
include\internal/pycore_backoff.h(66): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal/pycore_backoff.h(65): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax
include\internal/pycore_backoff.h(84): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal/pycore_backoff.h(83): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax
include\internal\pycore_tracemalloc.h(63): warning C4200: nonstandard extension used: zero-sized array in struct/union
include\internal\pycore_tracemalloc.h(63): note: This member will be ignored by a defaulted constructor or copy/move assignment operator
include\internal\pycore_stackref.h(372): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(372): error C2737: 'PyStackRef_ERROR': const object must be initialized
include\internal\pycore_stackref.h(376): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(376): error C2737: 'PyStackRef_ZERO_BITS': const object must be initialized
include\internal\pycore_stackref.h(390): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(390): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax
include\internal\pycore_stackref.h(435): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(435): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax
include\internal\pycore_stackref.h(452): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(452): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax
include\internal\pycore_stackref.h(466): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(466): error C2737: 'PyStackRef_NULL': const object must be initialized
include\internal\pycore_stackref.h(563): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(563): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax
include\internal\pycore_stackref.h(574): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(574): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax
include\internal\pycore_stackref.h(589): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(589): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax
include\internal\pycore_stackref.h(593): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(593): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax
include\internal\pycore_stackref.h(604): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(604): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax
include\internal\pycore_stackref.h(615): error C7555: use of designated initializers requires at least '/std:c++20'
include\internal\pycore_stackref.h(615): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax
error: command 'C:\\Program Files\\Microsoft Visual Studio\\2022\\Community\\VC\\Tools\\MSVC\\14.44.35207\\bin\\HostX86\\x64\\cl.exe' failed with exit code 2
error: subprocess-exited-with-error

[vstinner]

!buildbot AMD64 Windows11 Non-Debug

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @vstinner for commit 8c9afa5 🤖

Results will be shown at:

https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F144628%2Fmerge

The command will test the builders whose names match following regular expression: AMD64 Windows11 Non-Debug

The builders matched are:

• AMD64 Windows11 Non-Debug PR

[vstinner]

"AMD64 Windows11 Non-Debug PR" job is waiting for 2 hours for a Refleak job to complete. I will not wait longer for this job to run.

Hugo asked for a fix for Tuesday to prepare Python releases. I tested my fix locally, so let me merge this fix. We will see later if my fix works on the buildbot.