anchor.diff: -{ lib, stdenv, fetchurl, mecab, kytea, libedit, pkg-config
  +{ lib, stdenv, fetchurl, autoreconfHook, mecab, kytea, libedit, pkg-config
   , suggestSupport ? false, zeromq, libevent, msgpack
   , lz4Support  ? false, lz4
   , zlibSupport ? false, zlib
  -, autoconf, automake
   }:
   
   stdenv.mkDerivation rec {
  
positive.code:     ++ optional zlibSupport zlib
      ++ optionals suggestSupport [ zeromq libevent msgpack ];
  
    nativeBuildInputs = [ autoconf automake pkg-config ];
  
    configureFlags = with lib;
         optional zlibSupport "--with-zlib"
  
negative.code:   };
  
    preConfigure = ''
      # To avoid problems due to libc++abi 11 using `#include <version>`.
      rm version
    '';
  
    buildInputs = with lib;
  