nixpkgs.flake.setNixPath

Whether to set NIX_PATH to include nixpkgs=flake:nixpkgs such that <nixpkgs> lookups receive the version of nixpkgs that the system was built with, in concert with nixpkgs.flake.setFlakeRegistry.

This is on by default for nix-darwin configurations built with flakes.

This makes nix-build '<nixpkgs>' -A hello work out of the box on flake systems.

Note that this option makes the nix-darwin closure depend on the nixpkgs sources, which may add undesired closure size if the system will not have any nix commands run on it.