bug#6784: 24.0.50; cmdproxy incosistency with command pathnames

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 03 Aug 2010 23:57:16 +0300
> From: Laimonas Vėbra <laimonas.vebra@gmail.com>
> CC: 6784@debbugs.gnu.org
> 
> Laimonas Vėbra wrote:
> 
> > I guess, that CreateProcess(), in this case, internally processes
> > command line args, i.e. program names/paths ('c:/cygwin/bin/ls',
> > 'grep'), that it passes to cmd.exe and because command name/path is not
> > correctly/appropriately constructed (should be backslashed), it (chain
> > CreateProcess()->cmd.exe) fails.
> 
> Wrong. Actually it's cmd.exe that fails if command string contains pipe 
> and (subsequent slashed, not backslashed) program names are not quoted.
> 
> Works:
> cmd.exe /c c:/cygwin/bin/ls | grep foo
> cmd.exe /c c:/cygwin/bin/ls | C:\cygwin\bin\grep foo
> cmd.exe /c c:/cygwin/bin/ls | "C:/cygwin/bin/grep" foo
> cmd.exe /c "c:/cygwin/bin/ls" | "C:/cygwin/bin/grep" foo
> 
> Fails:
> cmd.exe /c c:/cygwin/bin/ls | C:/cygwin/bin/grep foo

In the case in point, the problem was with the executable _before_
the pipe.