Tootfinder

Yeah, why not neglect all the good recommendations in the #Python ecosystem, and instead fork your own C extension package, force people to build it with #ZigLang (it's still C), add unconditional dependency on that, and on top of that, refuse to publish wheels, "allowing for optimised compilation according to your machine's specific architecture and capabilities, instead of some (low performance) common denominator."
Fortunately, looks like #Gentoo can just ignore all the fancy crap and compile it with GCC.
https://pypi.org/project/ruamel.yaml.clibz/
[UPDATE: didn't last long: https://sourceforge.net/p/ruamel-yaml/code/ci/6846cf136e775ed0052cdef6ff02330269c86011/]