On Windows we need to use _stati64/_fstati64 in order to handle large
file sizes, but the handling was broken in the canned MSVC++
configuration. Clean it up and fix it.
This addresses BR 3392398.
Reported-by: Nikolai Saoukh <nms@otdel-1.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>