wip: dnsc-machine setup

hosts/dnsc-machine/default.nix

@@ -7,7 +7,7 @@
 }:
 
 let
-  backportPkgs = inputs.nixpkgs-backport-fix.legacyPackages.${pkgs.system};
+  backportPkgs = inputs.nixpkgs-backport-fix.legacyPackages.${pkgs.stdenv.hostPlatform.system};
 in
 {
   imports = [
@@ -40,6 +40,19 @@ in
         }
       );
     })
+    (final: prev: {
+      python313Packages = prev.python313Packages.overrideScope (
+        pyFinal: pyPrev: {
+          python-dbusmock = pyPrev.python-dbusmock.overridePythonAttrs (old: {
+            # take the *source* (or patches) from the backport
+            src = backportPkgs.python313Packages.python-dbusmock.src;
+
+            # optional but often needed
+            patches = (old.patches or [ ]) ++ (backportPkgs.python313Packages.python-dbusmock.patches or [ ]);
+          });
+        }
+      );
+    })
   ];
 
   # General settings