Add zenoh-c-from-source Conan recipe

[oteffahi]

This PR adds a conan recipe that builds Zenoh-C from source.

Specifically, this recipe builds a zenoh-c version (currently only 0.10.1-rc) from source using Rust compiler and cmake.

Note: The recipe assumes the appropriate Rust toolchain version is installed on the host (1.72.0 in case of 0.10.1-rc)

[gregmedd]

This worked for me. I was able to build another conan package (up-zenoh-client-cpp) using zenohc/0.10.1-rc as a dependency.

[gregmedd]

I'm not very experienced with conan packaging, so forgive me if the answer to this is obvious: Is there a way to build whatever is currently checked out in the git repo? There may be times where we want to test downstream projects using a specific commit of zenoh-c.

[oteffahi]

@gregmedd it is possible to have a recipe that checks out a specific commit. However it would require a different logic for the "source" function. Another challenge to take into account is the expected Rust version which can vary between commits.
Finally, this feature breaks CCI's recipe rule about only supporting stable releases in the recipes. But I guess we're already past that point 😅

Is this something you would like to see in this recipe?

[gregmedd]

@oteffahi That makes sense. Let's keep this recipe as is - better to have something that is correct and in line with what CCI would want, even this can't be submitted there yet. If we do ever find a need to build a development package, we'll figure out how to do it then.

Feel free to mark this comment resolved.

[oteffahi]

@gregmedd We've experimented with compiling specific commits, and it seems pretty straight-forward to add. As far as I know this not in-line with CCI's recipe requirements, but since we're managing our own recipe we might as well add exclusive features that cannot be supported otherwise 😄