Ah, right, I forgot about those issues (I'm thankful I don't write that sort of code myself - I can't say I ever enjoyed C even if I used to use it regularly many years ago). I guess PEP 725 is meant to address this sort of thing, too (as well as build-time requirements like compilers)... ?

I guess one possible workaround is to automate making a wheel for each version of the compiled library, and have the wheel version move in lockstep. Then you just specify the exact wheel versions in your dependencies, and infer the paths according to the wheel package names... it certainly doesn't sound pleasant, though. And, C being what it is, I'm sure that still overlooks something.