nix: Increase max-call-depth to fix stack overflow

Ref:
- NixOS/nix#9627
- nix-community/robotnix#224

modules/nixos/base.nix

@@ -66,6 +66,12 @@ in
     registry.nixpkgs.flake = flake.inputs.nixpkgs; # Make `nix shell` etc use pinned nixpkgs
     settings = {
       max-jobs = "auto";
+
+      # To workaround "stack overflow; max-call-depth exceeded" error from latest Nix when building nammayatri:
+      # https://github.com/NixOS/nix/issues/9627
+      # https://github.com/nix-community/robotnix/issues/224
+      max-call-depth = 10000000;
+
       experimental-features = "nix-command flakes";
       # Nullify the registry for purity.
       flake-registry = builtins.toFile "empty-flake-registry.json" ''{"flakes":[],"version":2}'';