configure fails for libstdc++-v3 under hpux 10.20 DCE threads

[law@redhat.com]

  In message < 200011171943.OAA27597@hiauly1.hia.nrc.ca >you write:
  > If I recall, this is a problem on the pa due to the lack of good
  > instructions for the purpose.  I am enclosing atomic.h and system.h from
  > the parisc-linux project in the hope that gives some clues how to solve
  > the problem.
Well, you use load & clear word to get a lock.  There aren't any other
instructions that are particularly interesting for snagging locks.

I'd tried to build v3 on my hpux boxes last week, but it failed in more
ways than I care to contemplate right now.  I'm hoping someone can start
putting the scaffolding in and that I can help with testing & polishing of
the hpux v3 support.

jeff