anchor.diff:  { lib, stdenv, fetchurl, fetchFromGitHub, perl, curl, bzip2, sqlite, openssl ? null, xz
   , pkgconfig, boehmgc, perlPackages, libsodium, aws-sdk-cpp, brotli, readline
   , autoreconfHook, autoconf-archive, bison, flex, libxml2, libxslt, docbook5, docbook5_xsl
  -, libseccomp, busybox
  +, libseccomp, busybox, nlohmann_json
   , hostPlatform
   , storeDir ? "/nix/store"
   , stateDir ? "/nix/var"
  
positive.code: 
    nixUnstable = (lib.lowPrio (common rec {
      name = "nix-1.12${suffix}";
      suffix = "pre5511_c94f3d55";
      src = fetchFromGitHub {
        owner = "NixOS";
        repo = "nix";
        rev = "c94f3d5575d7af5403274d1e9e2f3c9d72989751";
        sha256 = "1akfzzm4f07wj6l7za916xv5rnh71pk3vl8dphgradjfqb37bv18";
      };
      fromGit = true;
    })) // { perl-bindings = perl-bindings { nix = nixUnstable; }; };
  
negative.code: 
      buildInputs = [ curl openssl sqlite xz ]
        ++ lib.optional (stdenv.isLinux || stdenv.isDarwin) libsodium
        ++ lib.optionals fromGit [ brotli readline nlohmann_json ] # Since 1.12
        ++ lib.optional stdenv.isLinux libseccomp
        ++ lib.optional ((stdenv.isLinux || stdenv.isDarwin) && is112)
            (aws-sdk-cpp.override {
  