bug#23577: 24.5; emacs_backtrace.txt

[Drew Adams <drew.adams@oracle.com>]

> It would actually be better to not create bug reports that look like this.
> I'm
> not sure any of them have ever resulted in positive action, since no one can
> make heads or tails of the trace.

Fine.  I'll be glad to oblige.  Can you define "look like this"?

You're not sure that any of them have ever resulted in
positive action, but it is definitely the case that several
of the emacs_backtrace.txt reports I've filed have been resolved,
thanks to the info in the backtrace files.  (None recently, it
is true.)  All of those that were resolved also looked, to me,
"like this".  But perhaps not to the informed eye.

I guess I'll just not send any emacs_backtrace.txt reports in
the future.  Is there a way for me to prevent Emacs from
writing such useless files, and return to the way things were
before Emacs started cleverly writing them?  I certainly have
no need for them, if they are not helpful to report.  How to
turn off this "feature"?

Better yet would be for Emacs to write only useful ones, if
possible.  If it cannot write something useful, why write
anything?

Eli calls out to whoever built the Emacs binary to provide
extra information, to help decipher the backtrace.  Juanma
did that in the past, for his binaries.  But in this case
the binary was built and distributed by GNU Emacs, I believe
- it is the 24.5.1 release, AFAIK.

I no longer see releases in directory /gnu/emacs/windows/,
however.  All that is there now are Emacs 25 pretests.
(And do these pretest binaries have the magic sauce that
would make their emacs_backtrace files useful?  I don't
think so.)

(And BTW, why is there a windows/ directory of pretests at
the top level there, in addition to there being a windows/
directory under each of the other directories, pretest/ and
pretests/?)