fix: Add libz to FHS as required by Nuitka

CONTRIBUTING.md

@@ -13,7 +13,7 @@ OneLauncher uses [Poetry](https://python-poetry.org) for dependency management.
 
 OneLauncher comes with a [Nix](https://nixos.org/) flake for easily replicating the standard development environment. It can be used with [direnv](https://github.com/direnv/direnv) or the `nix develop` command. When using Nix, dependencies aren't installed with poetry. `poetry add`, ect can still be used for editing the dependency files, but `poetry run` should not be used.
 
-The easiest way to test compiled builds on NixOS is to use `steam-run`. Ex: `nix run nixpkgs#steam-run build/out/onelauncher.bin`.
+The compiled builds can be tested on NixOS with `nix run .#fhs-run build/out/onelauncher.bin`.
 
 ## Building
 

flake.nix

@@ -65,6 +65,12 @@
       packages = {
         onelauncher = poetry_app;
         default = self.packages.${system}.onelauncher;
+        fhs-run =
+          (pkgs.steam-fhsenv-without-steam.override {
+            # steam-unwrapped = null;
+            extraPkgs = pkgs: [pkgs.libz];
+          })
+          .run;
       };
       devShells.default = pkgs.mkShell {
         inputsFrom = [poetry_env.env];