The original freedesktop pkg-config implementation we use is pretty dead (no stable release since 2017, no commits in 3 years, no code changes since 2019), and has a variety of issues, including an awkward circular GLib dependency that makes bootstrapping more annoying, and missing support for useful .pc features.

pkgconf is a compatible from‐scratch reimplementation that avoids all these issues; they have a (biased, naturally, but still) comparison to pkg-config. Fedora has already moved to pkgconf as its pkg-config implementation, as have Arch, Alpine, and Debian.

@reckenrode will be using pkgconf in the Darwin SDK rework because of build issues with pkg-config’s vendored GLib, so the problems here are not just theoretical. I think we should strongly consider moving wholesale to pkgconf.