kgio provides non-blocking I/O methods for Ruby without raising
exceptions on EAGAIN and EINPROGRESS. It is intended for use with the
Unicorn and Rainbows! Rack servers, but may be used by other
applications.

* http://unicorn.bogomips.org/kgio/
* mongrel-unicorn@rubyforge.org />* git://git.bogomips.org/kgio.git

Changes:

* add compatibility for ancient Rubies (1.8.6)
* linux: fix accept4() support for newer Linux