ITS#10039 Test for SSL_CTX_set_ciphersuites()
This is the new version of the previously closed MR !612 (closed) which I am reopening as explained in the bug tracker.
https://bugs.openldap.org/show_bug.cgi?id=10039#c7
When configuring OpenLDAP using --with-tls=openssl with LibreSSL the configure will fail to detect SSL_export_keyring_material_early() since LibreSSL doesn't support this function yet. However OpenLDAP doesn't actually use this function and only checks for it to ensure a modern OpenSSL API is used. This can be easily solved by checking for an equivalent modern OpenSSL function which both LibreSSL and OpenSSL both
support such as SSL_CTX_set_ciphersuites(). Doing this allows the build and tests to succeed with modern LibreSSL versions. This was tested with LibreSSL >= 3.6.