anchor.diff:      optionals
       platforms;
   
  -  version = "4.13";
  +  version = "4.13.1";
   
     baseUrls = [
       "https://ftp.mozilla.org/pub/mozilla.org/nspr/releases/v${version}/src"
  
positive.code: 
    src = fetchurl {
      urls = map (n: "${n}/nspr-${version}.tar.gz") baseUrls;
      sha256Urls = map (n: "${n}/SHA256SUMS") baseUrls;
      sha256 = "19c33334bb3fa6d24800ffa65d7d806c54ad5f8c3758a5c11352ad43212ab181";
    };
  
    prePatch = ''
  
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";
  