anchor.diff:      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;
  
positive.code:     updateWalker = true;
    };
  }
  
negative.code: { stdenv, fetchurl, libxml2, gnutls, libxslt, pkgconfig, libgcrypt, libtool
  , openssl, nss, lib, runCommandCC, writeText }:
  
  lib.fix (self:
  let
    version = "1.2.28";
  in
  