20050205:
  AFFECTS: users of lang/ruby16_r, lang/ruby18_r, and lang/ruby18
  AUTHOR: knu@FreeBSD.org

  The slippery pthread support for systems prior to 502102 has been
  dropped and lang/ruby16_r and lang/ruby18_r ports have been removed,
  since no one seems to appreciate the partially working solution.

  Good news is that the pthread support of lang/ruby18 is now enabled
  by default for newer systems, which means the ruby interpreter is
  linked with libpthread. This will allow threaded extension
  libraries to run and work properly on those systems.