{nix,flake}: add submodules

flake.nix

@@ -2,8 +2,16 @@
   description = "PolyMC flake";
   inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
   inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs.libnbtplusplus = {
+    url = "github:multimc/libnbtplusplus";
+    flake = false;
+  };
+  inputs.quazip = {
+    url = "github:multimc/quazip";
+    flake = false;
+  };
 
-  outputs = inputs@{ self, nixpkgs, flake-utils,... }:
+  outputs = inputs@{ self, nixpkgs, flake-utils, libnbtplusplus, quazip, ... }:
     flake-utils.lib.eachSystem [ "x86_64-linux" "aarch64-linux" ] (system:
       let
         pkgs = import nixpkgs {
@@ -11,9 +19,17 @@
         };
  
         packages = {
-          polymc = pkgs.libsForQt5.callPackage ./packages/nix/polymc { inherit self; };
+          polymc = pkgs.libsForQt5.callPackage ./packages/nix/polymc {
+            inherit self;
+            submoduleQuazip = quazip;
+            submoduleNbt = libnbtplusplus;
+          };
         };
-        
+
+        overlay = import ./packages/nix/overlay.nix {
+          inherit self quazip libnbtplusplus;
+        };
+
         apps = {
           polymc = flake-utils.lib.mkApp {
             name = "PolyMC";
@@ -22,11 +38,9 @@
         };
       in
       {
-        inherit packages apps;
-
+        inherit packages overlay apps;
         defaultPackage = packages.polymc;
         defaultApp = apps.polymc;
-        overlay = import ./packages/nix/overlay.nix { inherit self; };
       }
     );
 }