add gtk4.nix for gtk development dependencies

gtk4.nix

@@ -0,0 +1,24 @@
+# gtk4.nix
+# Install GTK4/Libadwaita and other dependencies for common Pardus Apps/GTK Development
+let
+  pkgs = import <nixpkgs> {};
+in pkgs.mkShell {
+  packages = [
+    pkgs.gtk4
+    pkgs.gobject-introspection
+    pkgs.pkg-config
+    pkgs.libnotify
+    pkgs.libadwaita
+    pkgs.dbus
+    pkgs.apt
+    pkgs.libsoup
+    (pkgs.python3.withPackages (python-pkgs: [
+      python-pkgs.pycairo
+      python-pkgs.pygobject3
+      python-pkgs.pydbus
+      python-pkgs.dbus-python
+      python-pkgs.python-apt
+      python-pkgs.debian
+    ]))
+  ];
+}