add hacks

flake.nix

@@ -223,7 +223,11 @@
                 _module.args = extraArgs // {
                   inherit hostRegistry inputs zentralwerk;
                 };
-                nixpkgs.overlays = [ self.overlay ];
+                nixpkgs = {
+                  overlays = [ self.overlay ];
+                  # hack that needed to be added 2022-03-2x
+                  pkgs = nixpkgs.legacyPackages.${system};
+                };
               })
 
               self.nixosModules.c3d2

modules/c3d2.nix

@@ -1,6 +1,6 @@
 # This module defines options for use by all C3D2 machines.
 
-{ config, lib, pkgs, ... }:
+{ options, config, lib, pkgs, ... }:
 
 let
   cfg = config.c3d2;
@@ -171,7 +171,9 @@ in
             (lib.attrsets.filterAttrs (n: v: v.ip6 != null) cfg.hosts)
         ));
 
-      programs.nncp.settings = lib.mkIf cfg.mergeNncpSettings cfg.nncp;
+      programs = lib.optionalAttrs (options.programs ? nncp) {
+        nncp.settings = lib.optionalAttrs cfg.mergeNncpSettings cfg.nncp;
+      };
 
       users.motd = lib.mkIf cfg.enableMotd (builtins.readFile ./motd);
 

modules/nncp.nix

@@ -3,7 +3,7 @@ with lib;
 
 let
   nncpCfgFile = "/run/nncp.hjson";
-  programCfg = config.programs.nncp;
+  programCfg = lib.optionalAttrs (config.programs ? nncp) config.programs.nncp;
   callerCfg = config.services.nncp.caller;
   daemonCfg = config.services.nncp.daemon;
   settingsFormat = pkgs.formats.json { };