Fix compilation with OpenSSL 3.0 (Fedora Rawhide)
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This merge request is automatically copied from !1267 (merged) orginally made by @ellert
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Compilation failed on Fedora Rawhide after openssl was updated to version 3.0.
This PR fixes the places where the compilation failed with errors.
In addition there are many new warnings about use of deprecated parts of the API. This PR is not trying to address those.