anchor.diff:  { stdenv, fetchgit, pkgconfig, libtoxcore-dev, qt5, openal, opencv,
     libsodium, libXScrnSaver, glib, gdk_pixbuf, gtk2, cairo,
     pango, atk, qrencode, ffmpeg, filter-audio, makeWrapper }:
  +
  +let
  +  revision = "2f6b5e052f2a625d506e83f880c5d68b49118f95";
  +in
   
   stdenv.mkDerivation rec {
     name = "qtox-dev-20150821";
   
     src = fetchgit {
         url = "https://github.com/tux3/qTox.git";
  -      rev = "2f6b5e052f2a625d506e83f880c5d68b49118f95";
  +      rev = "${revision}";
         md5 = "b2f9cf283136b6e558876ca2e6d128a3";
     };
   
  
positive.code:   enableParallelBuilding = true;
  
    meta = with stdenv.lib; {
      description = "QT Tox client";
      license = licenses.gpl3;
      maintainers = with maintainers; [ viric jgeerds ];
      platforms = platforms.all;
    };
  }
  
negative.code:   nativeBuildInputs = [ pkgconfig ];
  
    preConfigure = ''
      # patch .pro file for proper set of the git hash
      sed -i '/git rev-parse/d' qtox.pro
      sed -i 's/$$quote($$GIT_VERSION)/${revision}/' qtox.pro
      # since .pro have hardcoded paths, we need to explicitly set paths here
      export NIX_CFLAGS_COMPILE="$NIX_CFLAGS_COMPILE $(pkg-config --cflags glib-2.0)"
      export NIX_CFLAGS_COMPILE="$NIX_CFLAGS_COMPILE $(pkg-config --cflags gdk-pixbuf-2.0)"
      export NIX_CFLAGS_COMPILE="$NIX_CFLAGS_COMPILE $(pkg-config --cflags gtk+-2.0)"
  