anchor.diff:                cat ${gtkrc2} >"$gtkrc2"
             fi
   
  -          gtk3_settings="''${XDG_CONFIG_HOME:?}/gtk-3.0/settings.ini"
  +          gtk3_settings="''${XDG_CONFIG_HOME}/gtk-3.0/settings.ini"
             if ! [ -f "$gtk3_settings" ]
             then
                 mkdir -p "$(dirname "$gtk3_settings")"
  
positive.code:   '';
  
    activationScript = ''
      # The KDE icon cache is supposed to update itself automatically, but it uses
      # the timestamp on the icon theme directory as a trigger. This doesn't work
      # on NixOS because the timestamp never changes. As a workaround, delete the
  
negative.code:     # disastrous, so here we nuke references to the Nix store
      # in Trolltech.conf.  A better solution would be to stop
      # Qt from doing this wackiness in the first place.
      trolltech_conf="''${XDG_CONFIG_HOME}/Trolltech.conf"
      if [ -e "$trolltech_conf" ]; then
          ${sed} -i "$trolltech_conf" -e '/nix\\store\|nix\/store/ d'
      fi
  