bug#33050: 27.0.50; [macOS] Problem with process input with process-connection-type nil

[Eli Zaretskii]

> From: Filipp Gunbin <fgunbin@fastmail.fm>
> Cc: fitzsim@fitzsim.org,  33050@debbugs.gnu.org,  alan@idiocy.org
> Date: Thu, 25 Oct 2018 23:47:00 +0300
> 
> > Is this bug important to fix, or can it wait for Emacs 27?  If it
> > cannot wait, then setting process-connection-type non-nil is the only
> > way we can have it fixed on the release branch, because changes like
> > those which you propose for process.c can only go to master.
> 
> If someone could confirm that setting process-connection-type to t
> (ldap.el, line 649) doesn't break it on GNU/Linux, then I think it's
> good to have it on release branch.  This bug prevents at least
> eudc-expand-inline with ldap on macOS from working.

We could make the change conditional on macOS, if we want to be
extra-careful.