I have just checked into the main-branch CVS tree some revisions
to allow autoconf to decide whether the system has POSIX signals
or not, rather than relying on the platform os.h file to tell us.
This seems to be the only reasonable way to support all the
different versions of HPUX correctly.
I would like to check this into the 6.4 branch for 6.4.1, but
I'm afraid Marc will break my thumbs if I just do that without
any outside testing ;-). Please let me know whether this works
OK on your platform.
regards, tom lane