anchor.diff:  
     src = fetchurl {
       urls = map (n: "${n}/nspr-${version}.tar.gz") baseUrls;
  -    sha256Urls = map (n: "${n}/SHA256SUMS") baseUrls;
  -    sha256 = "19c33334bb3fa6d24800ffa65d7d806c54ad5f8c3758a5c11352ad43212ab181";
  +    hashOuput = false;
  +    sha256 = "5e4c1751339a76e7c772c0c04747488d7f8c98980b434dc846977e43117833ab";
     };
   
     prePatch = ''
  
positive.code:     optionals
      platforms;
  
    version = "4.13";
  
    baseUrls = [
      "https://ftp.mozilla.org/pub/mozilla.org/nspr/releases/v${version}/src"
  
negative.code:     find $out -name "*.a" -delete
    '';
  
    passthru = {
      srcVerification = fetchurl {
        inherit (src)
          outputHash
          outputHashAlgo
          urls;
        sha256Urls = map (n: "${n}/SHA256SUMS") baseUrls;
        failEarly = true;
      };
    };
  
    meta = with stdenv.lib; {
      homepage = http://www.mozilla.org/projects/nspr/;
      description = "Netscape Portable Runtime, a platform-neutral API for system-level and libc-like functions";
  