anchor.diff:    meta = {
       description = "A random number generator daemon";
       homepage = https://github.com/nhorman/rng-tools;
  -    license = stdenv.lib.licenses.gpl2Plus;
  -    platforms = stdenv.lib.platforms.linux;
  -    maintainers = with stdenv.lib.maintainers; [ johnazoidberg ];
  +    license = licenses.gpl2Plus;
  +    platforms = platforms.linux;
  +    maintainers = with maintainers; [ johnazoidberg ];
     };
   }
  
positive.code:   # Not sure if jitterentropy is safe to use for cryptography
    # and thus a default entropy source
  , jitterentropy ? null, withJitterEntropy ? false
  }:
  with stdenv.lib;
  stdenv.mkDerivation rec {
    name = "rng-tools-${version}";
    version = "6.6";
  
    src = fetchFromGitHub {
      owner = "nhorman";
      repo = "rng-tools";
      rev = "v${version}";
      sha256 = "0c32sxfvngdjzfmxn5ngc5yxwi8ij3yl216nhzyz9r31qi3m14v7";
    };
  
    nativeBuildInputs = [ libtool autoconf automake pkgconfig ];
  
    preConfigure = "./autogen.sh";
  
    configureFlags =
         optional (!withJitterEntropy) "--disable-jitterentropy"
      ++ optional (!withNistBeacon) "--without-nistbeacon"
      ++ optional (!withGcrypt) "--without-libgcrypt";
  
    buildInputs = [ sysfsutils ]
      ++ optional withJitterEntropy [ jitterentropy ]
      ++ optional withGcrypt [ libgcrypt.dev ]
      ++ optional withNistBeacon [ openssl.dev curl.dev libxml2.dev ];
  
    enableParallelBuilding = true;
  
  
negative.code: { stdenv, fetchFromGitHub, libtool, autoreconfHook, pkgconfig
  , sysfsutils
    # WARNING: DO NOT USE BEACON GENERATED VALUES AS SECRET CRYPTOGRAPHIC KEYS
    # https://www.nist.gov/programs-projects/nist-randomness-beacon
  