sleepy_penguin 3.5.0

Most notably, kevent and epoll_wait wrappers are now
nestable, so you can write your own event loops inside
somebody elses event loop (not that it's a good idea,
but hey, that's reality, sometimes).

  https://bogomips.org/sleepy_penguin/SleepyPenguin/Kqueue.html#method-i-kevent
  https://bogomips.org/sleepy_penguin/SleepyPenguin/Epoll.html#method-i-wait

For Linux users, there is now copy_file_range(2) support
for copying regular files:

  https://bogomips.org/sleepy_penguin/SleepyPenguin.html#method-c-copy_file_range

There is also a new sendfile wrapper which emulates Linux
sendfile behavior regardless of platform.  It will use the
native sendfile(2) syscall on FreeBSD and Linux, at least.

  https://bogomips.org/sleepy_penguin/SleepyPenguin.html#method-c-linux_sendfile

Wrappers for the splice(2) and tee(2) syscalls also exist for
Linux users (vmsplice(2) is omitted):

  https://bogomips.org/sleepy_penguin/SleepyPenguin.html#method-c-splice
  https://bogomips.org/sleepy_penguin/SleepyPenguin.html#method-c-tee

Along with some related constants:

  https://bogomips.org/sleepy_penguin/SleepyPenguin.html#F_GETPIPE_SZ
  https://bogomips.org/sleepy_penguin/SleepyPenguin.html#F_SETPIPE_SZ
  https://bogomips.org/sleepy_penguin/SleepyPenguin.html#F_MORE
  https://bogomips.org/sleepy_penguin/SleepyPenguin.html#F_MOVE
  https://bogomips.org/sleepy_penguin/SleepyPenguin.html#F_NONBLOCK

In other words, this release merges the useful parts of the old
"io_splice" RubyGem: https://bogomips.org/ruby_io_splice/

Linux 4.5+ epoll users also get EPOLLEXCLUSIVE along existing
constants:

  https://bogomips.org/sleepy_penguin/SleepyPenguin/Epoll.html#EXCLUSIVE

Ruby 1.8 and 1.9 support are both gone, Ruby 2.0.0+ is required
for keyword args, now(*).

31 changes since 3.4.1:

      README: fix wording: are => is
      TODO: add memfd item
      epoll: allow :CLOEXEC instead of the long constant
      note the epoll/io.rb file is only for Ruby 1.8
      support the splice(2) and tee(2) syscalls
      implement copy_file_range support for Linux 4.5+
      doc: various URL updates (https)
      unify rb_gc() handling for out-of-FD conditions
      splice: clarification regarding tee() flags
      pkg.mk: various updates from other projects
      copy_file_range: use correct syscall numbers on x86/x86-64
      new API for splice and tee
      doc: remove references to IO#pipe_size accessor
      remove PIPE_BUF constant definition
      copy_file_range: move wrapper to Ruby for keyword arg handling
      gemspec: use SPDX-compatible license specifier
      implement linux_sendfile support
      portability fixes for systems w/o splice, copy_file_range
      tests: switch to test-unit
      free buffer if pthread_setspecific fails
      allow nestable TLS buffers within the same thread
      drop unused Ruby 1.8 support code
      epoll: add newline to Kernel#warn messages for atomicity
      favor require_relative over require
      epoll: add EPOLLEXCLUSIVE constant and documentation
      kqueue: remove IO#autoclose= and 1.8-related checks
      sp_copy: remove dummy 1.8 code for non-native threaded Ruby
      build: remove build-time olddoc dependency
      copy_file_range: add documentation
      doc: tests and examples for changing pipe size in Linux
      doc: avoid incorrect links to Epoll::IO