anchor.diff:    buildFlags = [
       "USE_OPENSSL=yes"
       "USE_ZLIB=yes"
  +  ] ++ stdenv.lib.optionals usePcre [
  +    "USE_PCRE=yes"
  +    "USE_PCRE_JIT=yes"
  +  ] ++ stdenv.lib.optionals useLua [
  +    "USE_LUA=yes"
  +    "LUA_LIB=${lua}/lib"
  +    "LUA_INC=${lua}/include"
     ] ++ stdenv.lib.optional stdenv.isDarwin "CC=cc";
   
     meta = {
  
positive.code: { stdenv, pkgs, fetchurl, openssl, zlib }:
  
  stdenv.mkDerivation rec {
    pname = "haproxy";
  
negative.code:     sha256 = "ebb31550a5261091034f1b6ac7f4a8b9d79a8ce2a3ddcd7be5b5eb355c35ba65";
    };
  
    buildInputs = [ openssl zlib ]
      ++ stdenv.lib.optional useLua lua
      ++ stdenv.lib.optional usePcre pcre;
  
    # TODO: make it work on bsd as well
    makeFlags = [
  