bug#18133: Suppressing asynchronous command output

[Eli Zaretskii]

> From: Reuben Thomas <rrt@sc3d.org>
> Date: Wed, 21 Dec 2016 22:44:33 +0000
> Cc: 18133@debbugs.gnu.org
> 
>  I'm okay with adding this feature, but why turn it on by default right
>  away? The original discussion of this bug says nothing about making
>  this the default behavior. Perhaps it would be better to let users
>  use it first, and then turn it on by default if there's popular
>  demand?
> 
> Would a reasonable way to do this be to add a toggleable option to the 
> defcustom for display-buffer-alist, and
> document this in async-shell-command's docstring?

I think it could be.  Martin, WDYT?