bug#7785: bug#6784: bug#7785: rgrep is broken on woe32

[Eli Zaretskii <eliz@gnu.org>]

> From: Chong Yidong <cyd@stupidchicken.com>
> Cc: Sam Steingold <sds@gnu.org>, 7785@debbugs.gnu.org, 6784@debbugs.gnu.org
> Date: Sat, 08 Jan 2011 16:00:43 -0500
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > The discussions in that bug report concluded that the program file
> > name after the pipe needs to be quoted, in order for it to work with
> > file names that use forward- and back-slashes alike.  I can solve that
> > problem for rgrep (and for other similar commands) by tweaking the
> > templates used by grep.el, so as to quote the %s after the pipe
> > character `|'.  Would that be an okay solution?
> 
> I think this is an acceptable solution, and agree that changing cmdproxy
> to handle this intelligently sounds like a nightmare.

Okay, fixed in grep.el (revno 100367 on the emacs-23 branch).

> > The disadvantage is, of course, that similar solutions will have to be
> > implemented for each Emacs command that launches a shell pipeline.
> 
> Let's just fix these individually as the problems are reported.

I found only 2 more instances of this that need to be fixed.  One of
them is in jka-compr.el, where it calls `dd' in a pipe.  I fixed that
one.  The other one is in tramp.el, which uses shell pipelines a lot;
however, the only ones that need to be fixed are those that invoke
_local_ programs, not remote programs, as the latter will not be on a
Windows machine.  Michael, could you please take care of that (on the
emacs-23 branch)?  I gather that you have your master repository, so
doing it from there would be less hassle for you, and you know the
semantics of each pipeline better than I do.  Thanks.