TCP Fast Open in Linux 3.7 and later is now supported
in the client via Kgio::Socket#kgio_fastopen.

This release also adds the kgio_writev and
kgio_trywritev methods, thanks to funny-falcon

Fix build for platforms lacking both TCP_CORK _and_ TCP_NOPUSH
There are many test case fixes and cleanups, too.

Fixed build and autopush support under Debian GNU/kFreeBSD.
Test case fixes for timing-sensitive tests.

Fix a missing #include for Ruby 1.8.5 users.  No need to
upgrade to this (nor 2.7.1) if you're on a modern version
of Ruby.

This release fixes some compatibility issues with people
stuck on older versions of Ruby/RubyGems.

* define RARRAY_PTR/RARRAY_LEN macros for Ruby 1.8.6
* test/test_autopush: skip strace tests if not available
* gemspec: disable development dependencies for old systems

When running under Ruby trunk/2.0.0dev, all IO objects created
by kgio will be close-on-exec by default to match the (future)
2.0.0 behavior.  accept()ed sockets in kgio have always been
close-on-exec by default..

Singleton Kgio.accept_* methods are deprecated as the
kgio_accept/kgio_tryaccept methods all take an additional
flags argument.

There are various, test, documentation, and error message
improvements.

We now export SOCK_NONBLOCK, SOCK_CLOEXEC constants in the Kgio
namespace to make kgio_tryaccept/kgio_accept easier-to-use.
There are also some minor internal cleanups.

* Kgio::File.tryopen method added.  It is like File.open
  but won't raise exceptions.  The Kgio::File class includes
  Kgio::PipeMethods, so FIFOs opened through this get the
  kgio_* API.

* The kgio_wait_*able methods in Kgio::DefaultWaiters
  now accept an optional timeout argument.

* adds -lnsl and -lsocket checks for OpenSolaris

This release fixes a race condition that could allow
Errno::EINTR to be raised even though the 2.4.0 release
was supposed to stop that.

Nobody uses Kgio.poll, really, so this shouldn't be an issue
for real code, yet.