[Patch] Fixing the PROCESS_DUP_HANDLE security hole.

[Christopher Faylor]

With the current CVS, I am seeing the same (suboptimal) behavior on
Windows Me that I do in 1.5.12.

If I type a bunch of "sleep 60&" at the command line, then "bash" won't
exit until the last sleep 60 has terminated.  I can't explain why this
is.  It doesn't work that way on XP, of course.

While "bash" is waiting, I see no sign of it in the process table so
it's odd behavior.

The current CVS should work better with exim now, though.

cgf