bug#56025: 29.0.50; em-extpipe-test-2 times out on EMBA and Cygwin

[Jim Porter]

On 6/30/2022 8:52 PM, Jim Porter wrote:
> Normally, Eshell starts each process using ptys to control them. 
> However, the above Elisp code tells Eshell to use a pipe for "rev"[1]. 
> I'm not totally clear on all the subtleties here, but it seems to me 
> that it would make more sense for rev to use a pipe for its stdin and a 
> pty for its stdout. That's not possible with subprocesses in Emacs 
> though (as far as I know).

Oh, I forgot to mention that bug#56013 might be related to this in some 
way, since it exhibits some problems with ptys when used in Eshell 
pipelines too.