* dcrt0.cc (get_cygwin_startup_info): Change zeros to DWORD array.

	* dcrt0.cc (get_cygwin_startup_info): Change zeros to DWORD array.
	Expect first DWORD in child_info struct being set to non-zero if
	wincap.needs_count_in_si_lpres2 is set.  Add comment to explain why.
	* fork.cc (frok::parent): Set ch.zero[0] to a sensible count value
	if wincap.needs_count_in_si_lpres2 is set.
	* spawn.cc (spawn_guts): Ditto.  Add filler bytes after ch on stack
	to accomodate needs_count_in_si_lpres2.
	* wincap.h: Define needs_count_in_si_lpres2 throughout.
	* wincap.cc: Ditto.