try to build on unicron if it's available

modules/nix-settings.nix

@@ -2,6 +2,39 @@
 {
   nix.settings.experimental-features = [ "nix-command" "flakes" ];
   nix.settings.extra-experimental-features = [ "nix-command" "flakes" ];
+  nix.buildMachines = [{
+    hostName = "unicron";
+    system = "x86_64-linux";
+    protocol = "ssh-ng";
+    maxJobs = 0;
+  }];
+  nix.distributedBuilds = true;
+  nix.settings.builders = " ssh://unicron.local x86_64-linux " ;
+  nix.extraOptions = ''
+    builders-use-substitutes = true
+  '';
+  # dynamic linker
+  programs.nix-ld.enable = true;
+  programs.nix-ld.libraries = with pkgs; [
+    cmake
+    fontconfig
+    harfbuzz
+    freetype
+    expat
+    glib
+    atk 
+    gtk3 
+    pango
+    cairo
+    gdk-pixbuf 
+    zlib
+    xorg.libxcb
+    libxkbcommon
+    libGL
+    wayland
+    vulkan-headers
+    vulkan-loader
+  ];
   # Allow unfree packages
   nixpkgs.config.allowUnfree = true;
   nixpkgs.overlays = [ inputs.nur.overlay ];