cpu_limits.h for hpux

[law@redhat.com]

  > Here it is.  I've not actually tested this (on either pa or ia64),
  > but for certain the ia64 80 bit long double default isn't correct,
  > and it does seem that Jeff put the pa override in the wrong place.
  > 
  > Ok?
  > 
  > 
  > r~
  > 
  > 
  > 	* config/os/hpux/bits/os_defines.h: Don't define __glibcpp_long_bits.
  > 	* config/os/hpux/bits/cpu_limits.h: New file.
  > 	* configure.target (CPULIMITSH): Use it.
Thanks for cleaning this up.
jeff