flightgear: add .desktop file

pkgs/games/flightgear/default.nix

@@ -2,6 +2,7 @@
 , 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 {
@@ -18,6 +19,23 @@ stdenv.mkDerivation rec {
     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 = "${iconsrc}";
+    comment = "FlightGear Flight Simulator";
+    desktopName = "FlightGear";
+    genericName = "Flight simulator";
+    categories = "Game;Simulation";
+  };
+
   buildInputs = [
     freeglut freealut mesa libICE libjpeg openal openscenegraph plib
     libSM libunwind libX11 xproto libXext xextproto libXi inputproto
@@ -31,6 +49,9 @@ stdenv.mkDerivation rec {
   postInstall = ''
     mkdir -p "$out/share/FlightGear"
     tar xvf "${datasrc}" -C "$out/share/FlightGear/" --strip-components=1
+
+    mkdir -p "$out/share/applications/"
+    cp "${desktopItem}"/share/applications/* "$out/share/applications/"
   '';
 
   meta = with stdenv.lib; {