diff --git a/pkgs/games/cataclysm-dda/pkgs/default.nix b/pkgs/games/cataclysm-dda/pkgs/default.nix
index ee3f1b0f278..6f3df09a786 100644
--- a/pkgs/games/cataclysm-dda/pkgs/default.nix
+++ b/pkgs/games/cataclysm-dda/pkgs/default.nix
@@ -13,6 +13,8 @@ let
     };
   };
 
+  pkgs' = lib.mapAttrs (_: mod: lib.filterAttrs availableForBuild mod) pkgs;
+
   availableForBuild = _: mod:
   if isNull build then
     true
@@ -22,4 +24,4 @@ let
     mod.forCurses;
 in
 
-lib.mapAttrs (_: mod: lib.filterAttrs availableForBuild mod) pkgs
+lib.makeExtensible (_: pkgs')