anchor.diff:  
     buildPhase = ''
       mkdir -p "$out/include"
  -    cp -r vcglib "$out/include"
  -    export NIX_CFLAGS_COMPILE="$NIX_CFLAGS_COMPILE -I$out/include/vcglib"
       export NIX_LDFLAGS="-rpath $out/opt/meshlab $NIX_LDFLAGS"
       cd meshlab/src
       pushd external
  
positive.code: {stdenv, fetchurl, qt4, bzip2, lib3ds, levmar, muparser, unzip}:
  
  stdenv.mkDerivation rec {
    name = "meshlab-1.3.3";
  
negative.code: 
    sourceRoot = ".";
  
    buildInputs = [ qt4 unzip vcg ];
  
    meta = {
      description = "System for the processing and editing of unstructured 3D triangular meshes";
  