Patch attached.

I wasn't sure whether the API bump was warranted for such a trivial change.  But 
the fact is that some programs compiled prior to the patch will behave 
differently if they are recompiled after the patch.  For example, emacs limits 
the number of open subprocesses to FD_SETSIZE, so this number will change when 
emacs is recompiled for Cygwin 3.4.0.  Is that a good enough reason to bump the API?

Ken