make it possible to share code with openbsd. XXX gai_strerror() is now O(N), shouldn't matter too much
make it possible to share code with openbsd.
XXX gai_strerror() is now O(N), shouldn't matter too much

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame