Notes for reviewers:

• I moved the --disable-gil flag up in configure so that it comes before the debug check so that the optional "d" ABI flag appears on the outside (e.g., package-cpython-313td-darwin.so for --disable-gil --with-pydebug). This is purely aesthetic and can be changed, if you prefer.
• Contrary to what I originally thought, pypa/packaging will need to be updated to compute CPython tags for --disable-gil builds.

I included my suggested changes to be able to merge your PR more quickly ;-)

I included my suggested changes to be able to merge your PR more quickly ;-)

You need to regen configure.

You need to regen configure.

Oops. Otherwise, it would be too easy! Done.

Thanks!

Windows x64 unstable tests:

FAIL: test_future_times_out (test.test_concurrent_futures.test_as_completed.ThreadPoolAsCompletedTest.test_future_times_out) [0.01]

Should be already fixed by PR #109949.

FAIL: test_set_and_clear (test.test_threading.EventTests.test_set_and_clear)

I created issue #109974 for this failure.

Good, it got merged after a few CI hiccups :-)

The test broke test_importlib on Windows: see issue gh-110359.

FAIL: test_tagged_suffix (test.test_importlib.test_windows.Source_WindowsExtensionSuffixTests.test_tagged_suffix)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\Administrator\buildarea\3.x.itamaro-win64-srv-22-aws.x64.nogil\build\Lib\test\test_importlib\test_windows.py", line 122, in test_tagged_suffix
    self.assertIn(expected_tag, suffixes)
AssertionError: '_d.cp313-win32.pyd' not found in ['_d.cp313t-win_amd64.pyd', '_d.pyd']