
The instructions to install nixos behind a proxy were not clear. While one could guess that setting http_proxy variables can get the install rolling, one could end up with an installed system where the proxy settings for the nix-daemon are not configured. This commit updates the documentation with 1. steps to install behind a proxy 2. configure the global proxy settings so that nix-daemon can access internet. 3. Pointers to use nesting.clone in case one has to use different proxy settings on different networks.
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.