Fix NixOS GUI issues

Fixes #380, #414

shell.nix

@@ -1,6 +1,21 @@
 { pkgs ? import <nixpkgs> { } }:
 
+let
+  runtimeLibs = with pkgs; [
+    gtk3
+    webkitgtk_4_1
+    xdotool
+    libayatana-appindicator
+  ];
+
+  packages = with pkgs; [
+    cargo
+    rustc
+    pkg-config
+    kdePackages.kdialog
+  ] ++ runtimeLibs;
+in
 pkgs.mkShell {
-  buildInputs =
-    [ pkgs.cargo pkgs.rustc pkgs.webkitgtk pkgs.pkg-config pkgs.kdialog ];
+  buildInputs = packages;
+  LD_LIBRARY_PATH = pkgs.lib.makeLibraryPath runtimeLibs;
 }