anchor.diff:  # as autostart item.
   
   {stdenv, lib}:
  -{ name     # name of the desktop file (without .desktop)
  -, package  # package where the desktop file resides in
  +{ name            # name of the desktop file (without .desktop)
  +, package         # package where the desktop file resides in
  +, srcPrefix ? ""  # additional prefix that the desktop file may have in the 'package'
   , after ? null
   , condition ? null
   , phase ? "2"
  
positive.code:   # this will automatically put 'package' in the environment when you
    # put its startup item in there.
    propagatedBuildInputs = [ package ];
  }
negative.code:   buildCommand = ''
      ensureDir $out/share/autostart
      target=${name}.desktop
      cp ${package}/share/applications/${srcPrefix}${name}.desktop $target
      chmod +rw $target
      echo "X-KDE-autostart-phase=${phase}" >> $target
      ${lib.optionalString (after != null) ''echo "${after}" >> $target''}
  