f309440ee3
Nix commands inside the container have been broken since 18.03, and no fix is yet in sight. Lets remove from the documentation that this is a usecase that we support, as it doesn't seem likely that this will be fixed before 18.09 either. See #40355
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.