anchor.diff:  assert static || shared;
   
   let
  -  version = "1.2.10";
  +  version = "1.2.11";
   
     tarballUrls = version: [
       "http://zlib.net/zlib-${version}.tar.xz"
  
positive.code: 
    src = fetchurl {
      urls = tarballUrls version;
      multihash = "QmNdvd5s9vseKCdBQsHuk24B2XHnVNmyUziWQhetFPdroB";
      sha256 = "9612bf086047078ce3a1c154fc9052113fc1a2a97234a059da17a6299bd4dd32";
    };
  
    configureFlags = [
  
negative.code:   passthru = {
      srcVerification = fetchurl rec {
        failEarly = true;
        urls = tarballUrls "1.2.11";
        pgpsigUrls = map (n: "${n}.asc") urls;
        pgpKeyFingerprint = "5ED4 6A67 21D3 6558 7791  E2AA 783F CD8E 58BC AFBA";
        inherit (src) outputHashAlgo;
        outputHash = "4ff941449631ace0d4d203e3483be9dbc9da454084111f97ea0a2114e19bf066";
      };
    };
  
  