(previously: NixOS/nixpkgs#16455)

Currently, when installing macOS GUI applications like iTerm2 or Sequel Pro, you always have to manually symlink the applications from ~/.nix-profile/Applications to ~/Applications. This is bad user experience. E.g. homebrew cask can automatically do this for me.

Maybe we can find a way to do this automatically if the host OS is macOS. Let me know what you think about this idea :)