Grab bag of smaller OpenSSL fixups

I've been collecting a few small fixups to the OpenSSL code and figured it was
time to send them over to keep the number of fixes more manageable.

* 0001: Remove the use of static variable to not interfere with the future
multithreading efforts
* 0002: Replace SSLv23_method with TLS_method, it has been an alias to the new
name since 2015 in OpenSSL
* 0003: Replace deprecated API X509_NAME_get_text_by_NID with the recommended
alternative X509_NAME_get_index_by_NID + X509_NAME_get_entry. The API was
deprecated in OpenSSL 4 and risk getting removed, with the alternatives being
available in all supported versions.
* 0004: Fix TLS protocol detection. We have been using the wrong macro for
feature test for a long time, replace with the actual feature test macro.
(There is no protocol downgrade here, it will error out when misconfiguring).

None of these change existing functionality or introduce new functionality.

--
Daniel Gustafsson