anchor.diff:    postInstall = stdenv.lib.optionalString enableGui ''
       for x in generic ice40 ecp5; do
         wrapProgram $out/bin/nextpnr-$x \
  -        --prefix QT_PLUGIN_PATH : ${qtbase}/lib/qt-${qtbase.qtCompatVersion}/plugins
  +        --prefix QT_PLUGIN_PATH : "${qtbase}/${qtbase.qtPluginPrefix}"
       done
     '';
   
  
positive.code: in
  stdenv.mkDerivation rec {
    name = "nextpnr-${version}";
    version = "2019.02.20";
  
    src = fetchFromGitHub {
      owner  = "yosyshq";
      repo   = "nextpnr";
      rev    = "e8d3aaaf34895a073e4023192d97fc936d090990";
      sha256 = "0ijqpjnn7x16crd6cmd4nmgay320flizmjb7bbvg9hv464z3p4x7";
    };
  
    nativeBuildInputs = [ cmake makeWrapper ];
    buildInputs
       = [ boostPython python3 ]
      ++ (stdenv.lib.optional enableGui qtbase);
  
    enableParallelBuilding = true;
  
negative.code: { stdenv, fetchFromGitHub, cmake, makeWrapper
  , boost, python3, eigen
  , icestorm, trellis
  
  # TODO(thoughtpolice) Currently the GUI build seems broken at runtime on my
  