bug#29440: Tramp put drive_c in the backup file name when backuping in local PC/windows

[Eli Zaretskii]

> From: Michael Albinus <michael.albinus@gmx.de>
> Cc: shuguang@gmail.com,  29440@debbugs.gnu.org
> Date: Mon, 27 Nov 2017 21:21:02 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> Hi Eli,
> 
> > With your example, this produces
> >
> >   
> > "c:/Users/lb01177/AppData/Roaming/.emacs.d/backup/plink!!albinus@192.168.178.30!!!home!albinus!tmp!123"
> >
> > Or maybe prepend a slashe before calling subst-char-in-string?  That
> > would produce
> >
> >   
> > "c:/Users/lb01177/AppData/Roaming/.emacs.d/backup/!plink!!albinus@192.168.178.30!!!home!albinus!tmp!123"
> >
> > WDYT?
> 
> I'd prefer the second variant. It makes it more obvious where the file
> name is transformed from, keeping the leading slash.

OK, I installed such a change on the emacs-26 branch, please see if it
fixes the problem.