bug#12908: 24.3.50; file `emacs_backtrace.txt'?

[Drew Adams]

> > What is the file for, how are users to use it and control 
> > whether and where it is written, etc.?
> 
>         Implement backtrace output for fatal errors on MS-Windows.
>         * w32fns.c (CaptureStackBackTrace_proc): New typedef.
>         (BACKTRACE_LIMIT_MAX): New macro.
>         (w32_backtrace): New function.
>         (emacs_abort): Use w32_backtrace when the user chooses not to
>         attach a debugger.  Update the text of the abort dialog.
> 
> Currently you cannot control where it is written.

Thanks for the info.

Can you at least control _whether_ it is written?

> As for how to use it, if you have MinGW installed you can use 
> addr2line: addr2line -e /path/to/emacs.exe < emacs_backtrace.txt

(Which does what?)

If you do *not* have MinGW installed then is it the case that you can do nothing
with the file?  If so then, in that case at least, users should have an easy way
to turn off writing the file (which no one can use).

Is there some way (e.g. an env var to check?) that Emacs can itself know whether
MinGW is installed, so that at least in the case where it is not it can inhibit
writing the file (by default - obviously to be overridable by users)?

The file is not big (at least it wasn't in the case I had), so I don't mind
Emacs writing it, even though I cannot use it.  But I think users should be able
to control whether and where it gets written.

And I'm thinking that the default location should perhaps be somewhere under
.emacs.d, perhaps with the dir that is currently used as the default recorded
somehow.