anchor.diff:  { stdenv, fetchurl, libxml2, gnutls, libxslt, pkgconfig, libgcrypt, libtool
  -, openssl, nss }:
  +, openssl, nss, lib, runCommandCC, writeText }:
   
  +lib.fix (self:
   let
     version = "1.2.28";
   in
  
positive.code:     updateWalker = true;
    };
  }
  
negative.code:     moveToOutput "lib/xmlsec1Conf.sh" "$dev"
    '';
  
    passthru.tests.libxmlsec1-crypto = runCommandCC "libxmlsec1-crypto-test"
      {
        nativeBuildInputs = [ pkgconfig ];
        buildInputs = [ self libxml2 libxslt libtool ];
      } ''
      $CC $(pkg-config --cflags --libs xmlsec1) -o crypto-test ${writeText "crypto-test.c" ''
        #include <xmlsec/xmlsec.h>
        #include <xmlsec/crypto.h>
  
        int main(int argc, char **argv) {
          return xmlSecInit() ||
            xmlSecCryptoDLLoadLibrary(argc > 1 ? argv[1] : 0) ||
            xmlSecCryptoInit();
        }
      ''}
  
      for crypto in "" gcrypt gnutls nss openssl; do
        ./crypto-test $crypto
      done
      touch $out
    '';
  
    meta = {
      homepage = http://www.aleksey.com/xmlsec;
      downloadPage = https://www.aleksey.com/xmlsec/download.html;
  