bug#30208: M-x pdb breaks if certain characters are in the file's path

[Eli Zaretskii]

> From: Andreas Schwab <schwab@linux-m68k.org>
> Cc: eliz@gnu.org,  Robin.Allen@artsalliancemedia.com
> Date: Fri, 26 Jan 2018 17:35:48 +0100
> 
> >>   "^> \\([-a-zA-Z0-9_/.:\\@ 
> >> ]*\\|<string>\\)(\\([0-9]+\\))\\([a-zA-Z0-9_]*\\|\\?\\|<module>\\)()\\(->[^\n\r]*\\)?[\n\r]")
> >> 
> >> This is the default value, with @ (and space, for good measure) inserted 
> >> in the first group.
> >
> > Thanks, I made that change.  But why did you need to escape the @
> > character?  It isn't a special character in Emacs regular expressions,
> > AFAIK.
> 
> @ isn't escaped, it just happends to follow \ in the set of characters.

Right.