
Pantheon's greeter has numerous issues that cannot be fixed in a timely manner, and users are better off if they just didn't use it by default.
To build the manual, you need Nix installed on your system (no need for NixOS). To install Nix, follow the instructions at https://nixos.org/nix/download.html When you have Nix on your system, in the root directory of the project (i.e., `nixpkgs`), run: nix-build nixos/release.nix -A manual.x86_64-linux When this command successfully finishes, it will tell you where the manual got generated.