xdg-utils: add missing dependencies
xdg-utils: add missing dependencies

- Add coreutils to PATH, because the xdg scripts use other not yet
  provided coreutils like head.
  This makes the custom 'cut' and 'sort' functions obsolete.
  Remove double quotes around $out because $out contains no Bash field separators.
- Replace all instances of 'which' with 'type -P'.
  The previous sed command only replaced instances with a leading space.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs