On Thu, Oct 16, 2014 at 5:30 PM, Noam Postavsky
<npostavs@users.sourceforge.net> wrote:
> On Thu, Oct 16, 2014 at 1:06 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>> GNU Make overcomes this by detecting these cases, and invoking
>> CreateProcess in a special way (NULL as the first argument), see the
>> function process_begin there, around line 710 of sub_proc.c in the GNU
>> Make sources.  If you can come up with a way to do the same in Emacs,
>> by some suitable patch to cmdproxy.c, such a patch will be welcome
>> (assuming either the patch is small, or you will agree to sign legal
>> papers necessary for submitting substantial patches to FSF projects).
>
> I'll take a look (btw I have already signed for Emacs).

Patching cmdproxy.c fixes the call-process-shell-command case:

  (call-process-shell-command
   "\"c:/path with space/foo-bar.bat\" \"x &y\"" nil '(t t) t)

To fix the call-process case:

  (call-process
   "c:/path with space/foo-bar.bat" nil '(t t) t "x &y")

required a patch to w32proc.c. This is my first patch to Emacs proper;
hopefully I got everything in the right format.