bug#10483: [PATCH] cperl-mode: Avoid endless loop

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Fri, 04 Sep 2020 05:17:45 +0200
> Cc: 10483@debbugs.gnu.org
> 
> > I haven't found examples to steal from, and also missed the
> > fork/waitpid stuff which I use for such tasks in Perl.
> 
> Yeah...  Perhaps Emacs should grow some convenience functions for this
> stuff?

I don't think I understand what's missing in what we have already.
The equivalent of 'fork' is 'start-process', and the equivalent of
'waitpid' is a test of what 'process-status' returns.