NixOS/nixpkgs — pull request #5416 by nbp (2014-12-20 19:35:12+00:00)
Title: nixos-option: Support -I option

This gives the ability to set the configuration file or the NIX_PATH from the command line. This patch is forwarding the `-I` argument with its argument to the nix-instantiate calls made by nixos-option.

This patch is based on top of pull request #5405 and #5415, and fix the issue #2877.