fix_:override apple_sdk to use version 11.0 for macOS builds

- Updated overlay.nix to override the default `apple_sdk` version for macOS builds.
- Resolved issue with missing component of SDK in x86_64 builds by setting `darwin.apple_sdk` to `apple_sdk_11_0`.

nix/overlay.nix

@@ -70,4 +70,9 @@ in rec {
       })
     ];
   }));
-}
+
+  # Override darwin.apple_sdk globally
+  darwin = prev.darwin // {
+    apple_sdk = prev.darwin.apple_sdk_11_0;
+  }
+}