package myself; I chose Gentoo (and previously Arch) in part because its reasonably easy to package things there.

Most build systems are covered by eclasses ( libraries) that handle the repetitive minutia every package that build system needs.

Here's the tuba ebuild for example (from GURU, the Gentoo equivalent of the AUR), 90% of it is just listing the dependencies and telling it to use a few eclasses to handle everything else.

Oh, and here's the lemmy back end ebuild, the giant wall of crates is automatically generated/updated from a tool that reads the cargo files. (needed because Gentoo doesn't allow internet access during the build for normal packages so crates are downloaded ahead of time)