buildPgrxExtension: mark packages as broken on darwin

Because of [1], we can't run initdb / postgres inside the darwin
sandbox, even though it succeeds most of the time. It will lead to hard
to debug build failures eventually.

Since pgrx runs initdb as part of the build... there seems to be no
other way than marking those packages as broken for now. This could be
relaxed once [2] is available, because we could then disable the
checkPhase and all "initdb" for pgrx on darwin.

[1]:
https://github.com/NixOS/nixpkgs/issues/371242#issuecomment-2672697582
[2]: https://github.com/pgcentralfoundation/pgrx/pull/1994

pkgs/development/tools/rust/cargo-pgrx/buildPgrxExtension.nix

@@ -178,6 +178,11 @@ let
       (args.checkFeatures or [ ])
       ++ (lib.optionals usePgTestCheckFeature [ "pg_test" ])
       ++ [ "pg${pgrxPostgresMajor}" ];
+
+    meta = (args.meta or { }) // {
+      # See comment in postgresql's generic.nix doInstallCheck section
+      broken = (args.meta.broken or false) || stdenv.hostPlatform.isDarwin;
+    };
   };
 in
 rustPlatform.buildRustPackage finalArgs