retroarch: improvements

-  Added missing freedesktop items (`*.desktop` and icon).

    Note that for the moment, only added an `*.svg`
    icon as was the only available. It does not give
    us the best results (at least in xfce). We may decide
    later on to extract the content of the `*.ico` instead
    which is a bit more involved.

pkgs/misc/emulators/retroarch/default.nix

@@ -1,7 +1,21 @@
-{ stdenv, fetchgit, pkgconfig, ffmpeg, mesa, nvidia_cg_toolkit
+{ stdenv, fetchgit, makeDesktopItem, pkgconfig, ffmpeg, mesa, nvidia_cg_toolkit
 , freetype, libxml2, libv4l, coreutils, python34, which, udev, alsaLib
 , libX11, libXext, libXxf86vm, libXdmcp, SDL, libpulseaudio ? null }:
 
+let
+  desktopItem = makeDesktopItem {
+    name = "retroarch";
+    exec = "retroarch";
+    icon = "retroarch";
+    comment = "Multi-Engine Platform";
+    desktopName = "RetroArch";
+    genericName = "Libretro Frontend";    
+    categories = "Game;Emulator;";
+    #keywords = "multi;engine;emulator;xmb;";
+  };
+  
+in
+
 stdenv.mkDerivation rec {
   name = "retroarch-bare-${version}";
   version = "2015-11-20";
@@ -20,6 +34,14 @@ stdenv.mkDerivation rec {
     sed -e 's#/bin/true#${coreutils}/bin/true#' -i qb/qb.libs.sh
   '';
 
+  postInstall = ''
+    mkdir -p $out/share/icons/hicolor/scalable/apps
+    cp -p -T ./media/retroarch.svg $out/share/icons/hicolor/scalable/apps/retroarch.svg
+
+    mkdir -p "$out/share/applications"
+    cp ${desktopItem}/share/applications/* $out/share/applications
+  '';
+
   enableParallelBuilding = true;
 
   meta = with stdenv.lib; {

pkgs/misc/emulators/retroarch/wrapper.nix

@@ -18,6 +18,9 @@ stdenv.mkDerivation {
     do
       $(ln -s $coreDir/*.so $out/lib/.)
     done)
+
+    ln -s -t $out ${retroarch}/share
+
     makeWrapper ${retroarch}/bin/retroarch $out/bin/retroarch \
       --suffix-each LD_LIBRARY_PATH ':' "$cores" \
       --add-flags "-L $out/lib/ --menu" \