Prefer IO#wait_readable over IO#select. (#323)

Author: ioquatix

lib/irb/input-method.rb

@@ -84,8 +84,7 @@ def gets
  #
  # See IO#eof? for more information.
  def eof?
- rs, = IO.select([@stdin], [], [], 0.00001)
- if rs and rs[0]
+ if @stdin.wait_readable(0.00001)
  c = @stdin.getc
  result = c.nil? ? true : false
  @stdin.ungetc(c) unless c.nil?