bug#22975: 25.0.92; CANNOT_DUMP build can't start in tty mode

[Eli Zaretskii]

> From: Andreas Schwab <schwab@linux-m68k.org>
> Cc: Ken Raeburn <raeburn@raeburn.org>,  22975@debbugs.gnu.org
> Date: Fri, 11 Mar 2016 21:51:04 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > OK, I see.  So now it's crystal clear that bidi-display-reordering
> > should be bound to nil until loadup finishes, otherwise we are
> > playing with fire.
> >
> > Is there a way to know that the build CANNOT_DUMP from Lisp?
> 
> Would it be wrong to do this always?

I didn't mean to say it wasn't; the above 2 questions are 2 separate
issues.

> In temacs that is preparing to dump the value of
> bidi-display-reordering should make no difference.

You are right about -batch, but when temacs is run with -nw, we will
probably want to turn reordering on as soon as we can, because some
file or directory name, or maybe some message displayed during
loading, might require reordering.  (Being able to run "./temacs -nw"
is an important capability for debugging problems that happen due to
dumping.)  In fact, turning reordering off will display load path
incorrectly, if it includes R2L characters, but I see no way around
that (and I think when we display that, we don't yet have encoding and
decoding of file names set up, so we cannot reorder anyway).

> (A emacs that CANNOT_DUMP doesn't have dump-emacs.)

Right, thanks.