bug#24616: 26.0.50; No backtrace when emacsclient --eval fails

[Eli Zaretskii]

> From: Noam Postavsky <npostavs@users.sourceforge.net>
> Date: Tue, 4 Oct 2016 19:50:23 -0400
> Cc: 24616@debbugs.gnu.org
> 
> >>> $ emacsclient --eval '(progn (defun f () (error "foo")) (setq 
> >>> debug-on-error t) (f))'
> >>> *ERROR*: foo
> >>>
> >>> Note that there's no backtrace. This makes it almost impossible to debug
> >>> problems when using emacsclient.
> >>>
> >>
> >> Just a note: you can get a backtrace by setting debug-on-signal
> >> instead of debug-on-error.
> >
> > Really?
> >
> > $ emacsclient --eval '(progn (defun f () (error "foo")) (setq 
> > debug-on-signal t debug-on-error t) (f))'
> > *ERROR*: foo
> >
> > Am I missing something obvious?
> 
> The backtrace shows up in Emacs, where the server is running.

How about adding this to debugging.texi?