The next problem will be System V semaphores. I posted a patch[4] that uses macOS futexes to implement semaphores (pretty much the same way libc does on some other systems), which would fix that version of the problem. But you could presumably already use the more wasteful
named POSIX semaphores.

so I have an issue with users.users / users.knownUsers on nix-darwin; I'm trying to have nix-darwin create a user, but (after a bunch of swearing & reading the activate script in the built system closure) it seems to expect that the user needs to be deleted? here's what I configure, is there anything wrong with it?

  users.knownGroups = [ "ci-worker" ];
  users.knownUsers = [ "ci-worker" ];
  users.groups.ci-worker = {
    gid = 502;
  };
  users.users.ci-worker = {
    createHome = false;
    description = "Nix Build support user for remote builds from CI";
    home = "/var/empty";
    shell = pkgs.bashInteractive;
    name = "Nix Build CI Worker";
    uid = 502;
    gid = 502;
    openssh.authorizedKeys.keys = [
      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGFg7XQg/ACCFIL0f2OJoU0EIcQFuwa3qz7pQNzmDe2W root@gloria"
    ];
  };