Add support for OpenSSL 4.0.0 final

[vstinner]

OpenSSL 4.0.0 final was released yesterday (April 14th, 2026). We should updated the _ssl module to support this new version.

Linked PRs

• gh-148600: Add Modules/_ssl_data_40.h data #148601

[vstinner]

Python can be built with OpenSSL 4.0.0 using these commands:

python3 Tools/ssl/multissltests.py --steps=library --base-directory $HOME/multissl --openssl 4.0.0 --system Linux
./configure --with-pydebug --with-openssl=$HOME/multissl/openssl/4.0.0/
LD_LIBRARY_PATH=~/multissl/openssl/4.0.0/lib64/ make

See also issue gh-148292: test_urllib2_localnet fails with OpenSSL 4.0.0beta1.

See also PR gh-146217 which added support for OpenSSL 4.0.0 alpha1.