bug#31495: 26.1; filename completion -vs- "*"

[Tino Calancha]

> > +(defconst dired-enable-globstar-in-shell
> > +  '(("ksh" . "set -G")
> > +    ("bash" . "shopt -s globstar"))
> > +  "Alist of (SHELL . COMMAND), where COMMAND enables globstar in SHELL.
> > +If `dired-maybe-use-globstar' is non-nil, then `dired-insert-directory'
> > +checks this alist to enable globstar in the shell subprocess.")
>
> Shouldn't this be a defvar or a defcustom?  Using defconst makes it seem
> like the code wouldn't handle it being changed.
To indicate what shells Emacs is supporting for 
this feature.  Of course it might be a defvar, and users might change that adding other 
shells; but then, those shells might not been heavily tested by Emacs 
developers, and other features can break.
I just wanted to be conservative.

I think that is a cheap and useful addition.  I like it.
I set '/bin/sh' to '/bin/zsh' mainly to have globstar in dired; often,
I find that I reset it to 'bash' and globstar stop working with Dired :-(