anchor.diff:  
     enableParallelBuilding = true;
     doCheck = true;
  +  checkInputs = [ nss.tools ];
   
     # enable deprecated soap headers required by lasso
     # https://dev.entrouvert.org/issues/18771
  
positive.code: 
  lib.fix (self:
  let
    version = "1.2.28";
  in
  stdenv.mkDerivation {
    pname = "xmlsec";
  
negative.code: 
    src = fetchurl {
      url = "https://www.aleksey.com/xmlsec/download/xmlsec1-${version}.tar.gz";
      sha256 = "1j5bf7ni45jghyrbf7a14wx2pvfara557zyry7g7h8840c5kd11d";
    };
  
    patches = [
  