bug#51377: Automatically exit server when it has no remaining clients

[Gregory Heytings]

> If `save-buffers-kill-emacs' were called after that, the Emacs daemon 
> would be killed, losing the edits to bar.txt.

Indeed, you are correct.  Updated patch attached, which also takes care of 
running processes.

Option-to-automatically-stop-Emacs-server.patch
Description: Text Data