anchor.diff:  { stdenv
  -, ed
  +, bison
  +, fetchTritonPatch
   , fetchurl
   , flex
   
  
positive.code: }:
  
  stdenv.mkDerivation rec {
    name = "bc-1.07";
  
    src = fetchurl {
      url = "mirror://gnu/bc/${name}.tar.gz";
      hashOutput = false;
      sha256 = "55cf1fc33a728d7c3d386cc7b0cb556eb5bacf8e0cb5a3fcca7f109fc61205ad";
    };
  
    nativeBuildInputs = [
      ed
      flex
    ];
  
    buildInputs = [
      flex
      ncurses
      readline
    ];
  
    configureFlags = [
  
negative.code:     "--with-readline"
    ];
  
    postConfigure =
      /* Don't regen docs -- configure produces a small fragment
         that includes the version info which causes all pages to
         regen (newer file). */ ''
      	touch -r doc doc/*
      '';
  
    postBuild =
      /* Simple test */ ''
        echo "quit" | ./bc/bc -l Test/checklib.b
      '';
  
    doCheck = true;
  
    meta = with stdenv.lib; {
      description = "GNU software calculator";
  