bug#40271: 26.3; gdb-mode fails to initialize if the target executable is built without symbols

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 28 Mar 2020 15:11:27 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 40271@debbugs.gnu.org
> 
> > From: Vladimir Nikishkin <lockywolf@gmail.com>
> > Date: Sat, 28 Mar 2020 19:51:40 +0800
> > 
> > The way to reproduce would be the following:
> > 1)printf "program main\nend" > test.f90
> > 2)gfortran test.f90
> > 3)emacs -q
> > 4)M-: (setq gdb-many-windows t) RET
> > 5)gdb RET a.out RET
> > 
> > Observe that gdb-mode fails to initialize.
> 
> I cannot reproduce this on my system, debugging one of the programs in
> the public /usr/bin/ directory (which are all stripped of the
> debugging symbols).
> 
> > This happens because in gdb-mi.el.gz, line 4689, gdb-main-file gets
> > a completely unrelated .S file name relative to the directory where
> > distro authors compile glibc.
> 
> Please show all the related details (what regexp search fails, what
> does it find, and what it ought to find instead), since otherwise it
> will be very hard to fix this problem.

Also, if you start GDB from the shell prompt, like this:

  $ gdb -i=mi ./a.out

and then issue the -file-list-exec-source-file command, what do you
see?