anchor.diff:  
     impureEnvVars = lib.fetchers.proxyImpureEnvVars;
   } // (builtins.removeAttrs args [
  -  "name" "sha256" "cargoUpdateHook"
  +  "name" "sha256" "cargoUpdateHook" "nativeBuildInputs"
   ]))
  
positive.code: , patches ? []
  , sourceRoot ? ""
  , cargoUpdateHook ? ""
  , ...
  } @ args:
  
  
negative.code:   else throw "fetchCargoTarball requires a hash for ${name}";
  in stdenv.mkDerivation ({
    name = "${name}-vendor.tar.gz";
    nativeBuildInputs = [ cacert git cargo-vendor-normalise cargo ] ++ nativeBuildInputs;
  
    buildPhase = ''
      runHook preBuild
  