bitcoin: install desktop file and pixmaps

pkgs/applications/blockchains/bitcoin.nix

@@ -3,9 +3,24 @@
 , withGui }:
 
 with stdenv.lib;
-stdenv.mkDerivation rec{
+
-  pname = if withGui then "bitcoin" else "bitcoind";
+let
   version = "0.19.0.1";
+  majorMinorVersion = versions.majorMinor version;
+
+  desktop = fetchurl {
+    url = "https://raw.githubusercontent.com/bitcoin-core/packaging/${majorMinorVersion}/debian/bitcoin-qt.desktop";
+    sha256 = "0cpna0nxcd1dw3nnzli36nf9zj28d2g9jf5y0zl9j18lvanvniha";
+  };
+
+  pixmap = fetchurl {
+    url = "https://raw.githubusercontent.com/bitcoin/bitcoin/v${version}/share/pixmaps/bitcoin128.png";
+    sha256 = "08p7j7dg50jlj783kkgdw037klmx0spqjikaprmbkzgcb620r25d";
+  };
+
+in stdenv.mkDerivation rec {
+  pname = if withGui then "bitcoin" else "bitcoind";
+  inherit version;
 
   src = fetchurl {
     urls = [ "https://bitcoincore.org/bin/bitcoin-core-${version}/bitcoin-${version}.tar.gz"
@@ -22,6 +37,11 @@ stdenv.mkDerivation rec{
                   ++ optionals stdenv.isLinux [ utillinux ]
                   ++ optionals withGui [ qtbase qttools qrencode ];
 
+  postInstall = optional withGui ''
+    install -Dm644 ${desktop} $out/share/applications/bitcoin-qt.desktop
+    install -Dm644 ${pixmap} $out/share/pixmaps/bitcoin128.png
+  '';
+
   configureFlags = [ "--with-boost-libdir=${boost.out}/lib"
                      "--disable-bench"
                    ] ++ optionals (!doCheck) [