anchor.diff:  , freeglut, freealut, mesa, libICE, libjpeg, openal, openscenegraph, plib
   , libSM, libunwind, libX11, xproto, libXext, xextproto, libXi, inputproto
   , libXmu, libXt, simgear, zlib, boost, cmake, libpng, udev, fltk13, apr
  +, makeDesktopItem
   }:
   
   stdenv.mkDerivation rec {
  
positive.code:   postInstall = ''
      mkdir -p "$out/share/FlightGear"
      tar xvf "${datasrc}" -C "$out/share/FlightGear/" --strip-components=1
    '';
  
    meta = with stdenv.lib; {
  
negative.code:     sha256 = "0qjvcj2cz7ypa91v95lws44fg8c1p0pazv24ljkai2m2r0jgsv8k";
    };
  
    # Of all the files in the source and data archives, there doesn't seem to be
    # a decent icon :-)
    iconsrc = fetchurl {
      url = "http://wiki.flightgear.org/images/6/62/FlightGear_logo.png";
      sha256 = "1ikz413jia55vfnmx8iwrlxvx8p16ggm81mbrj66wam3q7s2dm5p";
    };
  
    desktopItem = makeDesktopItem {
      name = "flightgear";
      exec = "fgfs";
      icon = "${iconsrc}";
      comment = "FlightGear Flight Simulator";
      desktopName = "FlightGear";
      genericName = "Flight simulator";
      categories = "Game;Simulation";
    };
  
    buildInputs = [
      freeglut freealut mesa libICE libjpeg openal openscenegraph plib
      libSM libunwind libX11 xproto libXext xextproto libXi inputproto
  