bug#32051: 26.1; grep-regexp-alist on windows

[Eli Zaretskii <eliz@gnu.org>]

> From: Dan Harms <Dan.Harms@xrtrading.com>
> Date: Wed, 4 Jul 2018 12:14:41 +0000
> 
> Starting in emacsc 26.1, the grep-regexp-alist stopped matching grep
> hits that have a colon in them, which breaks on windows for me, since
> the file paths always have a drive letter prepended.
>  
> For example,
>  
> the grep hit:
>  
> c:/Users/my.name/src/project\src\kbhit.hpp:29:#include <termios.h>
>  
> used to be matched by prior versions of emacs, but as of 26.1, the
> colon in the second character prevents this from being recognized as a
> grep match.

I don't think I can reproduce this.  I've just ran a Grep command
whose hits look like this:

  d:/gnu/emacs/branch/src/callproc.c:214:#ifdef DOS_NT

and they seem to exhibit all the traits of a Grep hit.

What exactly do you mean by "prevents from being recognized as a grep
match"?  What doesn't happen that you expected to happen and that was
happening with prior versions of Emacs?  Also, does the problem go
away if you invoke Emacs as "emacs -Q"?