(catch 'system-error
    (lambda ()
      (match (clone (logior CLONE_NEWUSER SIGCHLD))
        (0
         (gc)                           ;create a garbage collection thread
         (sigaction SIGPIPE SIG_IGN)
         (unshare CLONE_THREAD)
         (primitive-exit 0))
        (pid
         (match (waitpid pid)
           ((_ . status)
            (zero? status))))))
    (lambda args
      (system-error-errno args)))