anchor.diff:  { stdenv
  -, ed
  +, bison
  +, fetchTritonPatch
   , fetchurl
   , flex
   
  
positive.code:     "--with-readline"
    ];
  
    # Prevent doc rebuild
    preBuild = ''
      touch doc doc/*
    '';
  
    doCheck =true;
  
    passthru = {
      srcVerification = fetchurl {
        failEarly = true;
        pgpsigUrls = map (n: "${n}.sig") src.urls;
        pgpKeyFingerprint = "00E4 2623 2F38 4BF6 D32D  8B18 81C2 4FF1 2FB7 B14B";
        inherit (src) urls outputHash outputHashAlgo;
      };
    };
  
    meta = with stdenv.lib; {
      description = "GNU software calculator";
  
negative.code: }:
  
  stdenv.mkDerivation rec {
    name = "bc-1.06.95";
  
    src = fetchurl {
      url = "http://alpha.gnu.org/gnu/bc/${name}.tar.bz2";
      multihash = "QmRDA6WLGngZ78WHmgJQrRgkkdkytf73iGVQPRe2MDJsUf";
      sha256 = "1k2yf9bhjxjwfhz0d1c5hmmrs8rxi9al0d4a39p8lgf0zayapr3y";
    };
  
    nativeBuildInputs = [
      bison
      flex
    ];
  
    buildInputs = [
      ncurses
      readline
    ];
  
    patches = [
      (fetchTritonPatch {
        rev = "4eaff4fc1ef159416bd98cf46c56dafa9d755a7a";
        file = "bc/bc-1.06-mem-leak.patch";
        sha256 = "27e30d0389b79556609a74a4bb2a19f208f0e527bf08357ad79e0f453f15ac17";
      })
      (fetchTritonPatch {
        rev = "4eaff4fc1ef159416bd98cf46c56dafa9d755a7a";
        file = "bc/bc-1.06-void_uninitialized.patch";
        sha256 = "cb210e21f6a9ab5cac591259b1649120b0b74a722dc02ec17cb09bc9a19f3b8a";
      })
    ];
  
    configureFlags = [
  