anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "root";
  -  version = "6.26.06";
  -
  -  src = fetchurl {
  -    url = "https://root.cern.ch/download/root_v${version}.source.tar.gz";
  -    hash = "sha256-sfc8l2pYClxWyMigFSWCod/FYLTdgOG3VFI3tl5sics=";
  +  version = "6.26.08";
  +
  +  src = fetchFromGitHub {
  +    owner = "root-project";
  +    repo = "root";
  +    rev = "v${builtins.replaceStrings [ "." ] [ "-" ] version}";
  +    sha256 = "sha256-cNd1GvEbO/a+WdDe8EHYGmdlw3TrOT2fWaSk+s7fw7U=";
     };
   
     nativeBuildInputs = [ makeWrapper cmake pkg-config git ];
  
positive.code: { stdenv
  , lib
  , fetchurl
  , fetchpatch
  , makeWrapper
  , cmake
  
negative.code: let
  
    _llvm_9 = llvm_9.overrideAttrs (prev: {
      patches = (prev.patches or [ ]) ++ [
        (fetchpatch {
          url = "https://github.com/root-project/root/commit/a9c961cf4613ff1f0ea50f188e4a4b0eb749b17d.diff";
          stripLen = 3;
  