v0.18.0

dtas 0.18.0

fiddle is now supported for Linux users without a C compiler or
Ruby headers installed to take advantage of inotify(7)
functionality and efficiency improvements with splice(2) and
eventfd(7).

For non-RubyGems users, there's some setup.rb fixes thanks
to James Rowe.

Eric Wong (8):
      doc: fixup leftover ftp://lists.gnu.org links
      pipe: avoid loading sleepy_penguin
      provide fiddle-based eventfd implementation
      buffer: replace sleepy_penguin with fiddle
      watchable: use fiddle for inotify support
      doc: remove most recommendations for sleepy_penguin
      INSTALL: s/bogomips.org/yhbt.net/
      doc: update copyrights for 2020

James Rowe (2):
      setup: update to use RbConfig
      setup: fix duplicate variable warning