anchor.diff:  { stdenv
   , lib
   , fetchFromGitHub
  -, fetchpatch
   , arpack
   , bison
   , blas
  
positive.code: 
  stdenv.mkDerivation rec {
    pname = "igraph";
    version = "0.9.1";
  
    src = fetchFromGitHub {
      owner = "igraph";
      repo = pname;
      rev = version;
      sha256 = "sha256-i6Zg6bfHZ9NHwqCouX9m9YqD0VtiWW8DEkxS0hdUyIE=";
    };
  
    patches = [
      (fetchpatch {
        name = "pkg-config-paths.patch";
        url = "https://github.com/igraph/igraph/commit/980521cc948777df471893f7b6de8f3e3916a3c0.patch";
        sha256 = "0mbq8v5h90c3dhgmyjazjvva3rn57qhnv7pkc9hlbqdln9gpqg0g";
      })
    ];
  
    # Normally, igraph wants us to call bootstrap.sh, which will call
    # tools/getversion.sh. Instead, we're going to put the version directly
  
negative.code:   outputs = [ "out" "dev" "doc" ];
  
    nativeBuildInputs = [
      bison
      cmake
      flex
      fop
      libxml2
      libxslt
  