configure --disable-threads

[Steven Parkes]

It looks to me like --disable-threads has itself been disabled.  In
configure, it looks like $enable_threads is supposed to take on one of
three states but if you use --disable-threads or --enable-threads=no,
later code changes the value back to '' which causes it to default
which, in the case of hpux, brings in dce threads.

The patch below isn't clean, but it shows where the issue occurs.

*** configure.orig	Sat Oct 17 15:37:14 1998
--- configure	Sat Oct 17 15:53:00 1998
***************
*** 825,831 ****
  if test "${enable_threads+set}" = set; then
    enableval="$enable_threads"
    if test x$enable_threads = xno; then
! 	enable_threads=''
  fi
  else
    enable_threads=''
--- 825,831 ----
  if test "${enable_threads+set}" = set; then
    enableval="$enable_threads"
    if test x$enable_threads = xno; then
! 	enable_threads='no'
  fi
  else
    enable_threads=''