[3.5] bpo-33127: Compatibility patch for LibreSSL 2.7.0 (GH-6210)

[aexvir]

LibreSSL 2.7 introduced OpenSSL 1.1.0 API. The ssl module now detects
LibreSSL 2.7 and only provides API shims for OpenSSL < 1.1.0 and
LibreSSL < 2.7.

Documentation updates and fixes for failing tests will be provided in
another patch set.

Signed-off-by: Christian Heimes christian@python.org

https://bugs.python.org/issue33127

[the-knights-who-say-ni]

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[larryhastings]

@tiran could you please review this and mark it as Approved on GitHub? That will make the workflow happy, and I'm sure all of us here want the computers to be happy.

[tiran]

@larryhastings The patch to _ssl.c looks goot to me. I verified that it fixes compilation with LibreSSL 2.7.5 and 2.8.3. Most tests are passing except for some known issues with LibreSSL.

I'd prefer to drop multissltest from the patch. The version from the PR is outdated.

[tiran]

ACK

Thanks, Larry 👍

[bedevere-bot]

@larryhastings: Please replace # with GH- in the commit message next time. Thanks!

[larryhastings]

Thanks, everybody! This is probably the last patch that'll go into 3.5.7.