Ruby io_splice 4.4.0 - minor updates

Most notably the mailing list is now subscription-optional
on the bogomips.org server:

    ruby-io-splice@bogomips.org

If you want to keep receiving email updates, you'll need to
resubscribe by sending a message to:

    ruby-io-splice+subscribe@bogomips.org

Migrating subscribers can't be done automatically as librelist
(our old host) doesn't publish subscriber lists.  But you don't
have to subscribe, either, HTTP archives are available at:

    http://bogomips.org/ruby-io-splice/

There you'll also find links to ssoma/public-inbox for
extracting the mail archives to git.

shortlog:
      move mailing list to ruby-io-splice@bogomips.org
      switch documentation to olddoc
      pack internal structs for 64-bit systems
      favor comparisons against zero instead of -1
      doc updates

Again, the io_splice 5.x will remove the mistake of the
IO::Splice.copy_stream method.  Users are encouraged to use
IO.copy_stream in Ruby (1.9+) itself instead.