anchor.diff:      "--no-faust"
     ] ++ optional optimizationSupport "--optimization";
   
  +  configurePhase = ''
  +    ./waf configure --prefix=$out $configureFlags
  +  '';
  +
     NIX_CFLAGS_COMPILE = [
       "-I${eigen}/include/eigen3"
     ];
  -
  -  configurePhase = ''
  -      ./waf configure --prefix=$out $configureFlags
  -    '';
   
     buildPhase = ''
       ./waf build
  
positive.code:   ];
  
    postPatch = ''
      patchShebangs waf
    '';
  
    configureFlags = [
  
negative.code:   inherit (stdenv.lib)
      optional;
  in
  stdenv.mkDerivation rec {
    name = "guitarix-${version}";
    version = "0.35.1";
  