We already have a LICENSE file that covers the Zig Standard Library. We
no longer need to remind everyone that the license is MIT in every single
file.
Previously this was introduced to clarify the situation for a fork of
Zig that made Zig's LICENSE file harder to find, and replaced it with
their own license that required annual payments to their company.
However that fork now appears to be dead. So there is no need to
reinforce the copyright notice in every single file.
On OpenBSD, connecting to a newly-allocated port on an unspecified IPv4
host address causes EINVAL. This was found by @mikdusan when running TCP
tests on OpenBSD.
This commit fixes TCP tests on OpenBSD by having all tests that allocate
a new host-port pair to have the host IPv4/IPv6 address point to the
host's loopback adapter (on localhost).
