How to build *all* of nixpkgs?

I can’t find any instructions for building all of nixpkgs, and nix-build doesn’t even try. No matter which reference I check out, even 21.05, I get this:

$ nix-build .
error: Please be informed that this pseudo-package is not the only part of
Nixpkgs that fails to evaluate. You should not evaluate entire Nixpkgs
without some special measures to handle failing packages, like those taken
by Hydra.

As for why, to see what it does, how long it takes, how much memory/disk space it needs, whether it’s stable, whether it can be optimised, whatever.

A good place to start may be GitHub - nix-community/nix-eval-jobs: Parallel nix evaluator with a streamable json output [maintainers @Mic92, @adisbladis]

Maybe you want to run a hydra instance? Say, similarly to the “official” jobsets like

For anyone really curious, there is the nix-env -i trick, which does exactly that - installs all of nixpkgs into user env.