iproute2 and libbpf: vendoring on the small scale

If you're going to try to do this kind of thing, and thus add a dependency, start with the oldest version of the library used by any still-supported version of a major distro. If you want to use newer features, that's fine, you can do feature-detection at compile time and use newer stuff if (and only if) it's there (as danobi mentions the bpftrace people do, in a comment above). Distros that happen to be on newer versions can thus take advantage of that, without introducing show-stoppers for distros that don't.

If instead you start off your refactoring by requiring a library version that's not even in the very latest version of a major distro, you're heading for trouble. When you hit it, saying it's the distro user's fault, and that they need to upgrade the library, isn't going to impress the user community, or speed up acceptance of your work.