anchor.diff:    #    used for bootstrapping, but koch insists on moving the nim compiler around
     #    as part of building it, so it cannot be read-only
   
  -  buildInputs  = [
  -    makeWrapper nodejs
  -    openssl pcre readline sqlite
  +  buildInputs = [
  +    makeWrapper nodejs-slim-8_x tzdata coreutils
  +    openssl pcre readline sqlite boehmgc sfml
     ];
   
  -  buildPhase   = ''
  +  buildPhase = ''
       sh build.sh
       ./bin/nim c koch
       ./koch boot  -d:release \
  
positive.code:     "-lpcre"
      "-lreadline"
      "-lsqlite3"
    ];
  
    # 1. nodejs is only needed for tests
  
negative.code: # based on https://github.com/nim-lang/Nim/blob/v0.18.0/.travis.yml
  
  { stdenv, lib, fetchurl, makeWrapper, nodejs-slim-8_x, openssl, pcre, readline, sqlite, boehmgc, sfml, tzdata, coreutils }:
  
  stdenv.mkDerivation rec {
    name = "nim-${version}";
    version = "0.18.0";
  
    src = fetchurl {
      url = "https://nim-lang.org/download/${name}.tar.xz";
      sha256 = "45c74adb35f08dfa9add1112ae17330e5d902ebb4a36e7046caee8b79e6f3bd0";
    };
  
    doCheck = true;
  