* hookapi.cc (hook_or_detect_cygwin): Take additional handle

	* hookapi.cc (hook_or_detect_cygwin): Take additional handle
	to a file mapping as parameter.  If this handle is not NULL,
	create another file mapping for the IAT.
	* spawn.cc (av::fixup): Only map the first 64K of an image and
	keep the mapping handle to use as argument to hook_or_detect_cygwin.
	* winsup.h (hook_or_detect_cygwin): Add mapping handle as default
	parameter in declaration.