There are some historical references to a problem with compiling Ruby
with pthread support for HPUX:

  http://www.codecomments.com/archive327-2005-4-470857.html

Although there is also a report here that it works:

  http://www.rubyweeklynews.org/20050424

It looks like the "fixed" report comes directly after the "broken" one,
and some of the same people are involved. I would expect that the
current sitaution is "fixed", but I've not been able to find a blazing,
40 point: "it works - go install it" that I can convince people here
with. Could anyone in the know, please confirm the current situation?

Thanks you very much,
  Benjohn