anchor.diff:    makeFlags = with stdenv.lib; [
       "PREFIX=$(out)"
       "LUA=1"
  -    "RELEASE=1"
       "USE_HOME_DIR=1"
       "LANGUAGES=all"
       "VERSION=git-${version}-${substring 0 8 src.rev}"
  
positive.code: { fetchFromGitHub, stdenv, pkgconfig, ncurses, lua, SDL2, SDL2_image, SDL2_ttf,
  SDL2_mixer, freetype, gettext, CoreFoundation, Cocoa,
  tiles ? true }:
  
  stdenv.mkDerivation rec {
    version = "2018-07-15";
  
negative.code:   ] ++ optionals stdenv.isDarwin [
      "NATIVE=osx"
      "CLANG=1"
    ] ++ optionals (! debug) [
      "RELEASE=1"
    ];
  
    postInstall = with stdenv.lib; optionalString (tiles && !stdenv.isDarwin) ''
  