anchor.diff: -{ lib, stdenv, buildPackages
  -, fetchurl, pkg-config, ncurses, gzip
  -, sslSupport ? true, openssl ? null
  +{ lib
  +, stdenv
  +, buildPackages
  +, fetchurl
  +, pkg-config
  +, ncurses
  +, gzip
  +, sslSupport ? true
  +, openssl
   , nukeReferences
   }:
  -
  -assert sslSupport -> openssl != null;
   
   stdenv.mkDerivation rec {
     pname = "lynx";
  
positive.code:   meta = with lib; {
      description = "A text-mode web browser";
      homepage = "https://lynx.invisible-island.net/";
      license = licenses.gpl2Plus;
      platforms = platforms.unix;
    };
  
negative.code:   nativeBuildInputs = [ nukeReferences ]
      ++ lib.optional sslSupport pkg-config;
  
    buildInputs = [ ncurses gzip ]
      ++ lib.optional sslSupport openssl;
  
    # cfg_defs.h captures lots of references to build-only dependencies, derived
    # from config.cache.
  