flake: add local-xwayland command for ad-hoc X usage

flake.nix

@@ -278,6 +278,16 @@
                     };
                   };
 
+
+                local-xwayland = pkgs.writeShellScriptBin "local-xwayland" ''
+                  set -x
+                  ${pkgs.wayland-proxy-virtwl}/bin/wayland-proxy-virtwl \
+                    --wayland-display=wayland-3 \
+                    --xwayland-binary=${pkgs.xwayland}/bin/Xwayland \
+                    --x-display=0 \
+                    # --x-unscale=3 \
+                    --verbose
+                  '';
               in
               {
                 dcpj4110dwDriver = dcpj4110dw.driver;
@@ -325,6 +335,8 @@
                   nativeBuildInputs = [ pkgs.pkg-config ];
                   buildInputs = [ ];
                 };
+
+                inherit local-xwayland;
               };
 
             formatter =