Upstream FindBotan.cmake to CMake project

[securitykernel]

It has been a long-term issue that CMake does not ship with a FindBotan.cmake find module to search for and link against a Botan installation. People start writing their own find modules again and again, that basically do the same, which you can see GitHub search, for example. For existing but also new users of Botan, it would be great if they had out-of-the-box support for Botan in CMake projects.

I found that the FindBotan script you ship with rnp looks the most mature and already supports Botan 2.x and 3.x. Would it be possible to upstream it to the CMake project? The only requirement from CMake's side would be to find a dedicated module maintainer. If none of you can do this, I would be willing to step in to make this happen.

/cc @randombit @reneme @lieser

[ni4]

@ronaldtse what do you think?
We already have separate repository for CMake modules, used in rnp: https://github.com/rnpgp/cmake-modules/
Actually never know/think before about upstreaming CMake modules to the CMake repository, but the idea itself looks good to me.

P.S. Thanks for raising this!

[securitykernel]

Any update on this?

[ni4]

@securitykernel Sorry for a delay. I absolutely don't mind moving it to upstream/CMake. However let's wait for @ronaldtse reply.

[securitykernel]

Sure, sounds fine!

[ronaldtse]

@securitykernel thank you for the suggestion! We'd be happy to contribute it upstream. Would you be willing to jointly maintain the module upstream?

[securitykernel]

Sure, let's do it!

[securitykernel]

Asked the CMake maintainers if it would be accepted. Waiting for their response. Meanwhile, I started to integrate it into their repo. Are you fine with re-licensing it to BSD 3-Clause License, as this is the default for all find modules shipped with CMake?

[ronaldtse]

@securitykernel yes we would be willing to re-license the module to BSD 3-clause -- BSD 2-clause is more general than BSD 3-clause so it is fine.

[securitykernel]

So we got everything right now, I think. Can you please test that randombit/botan#3722 works for you? That would give us a bit of more confirmation.