gcc conformance to HP-PA ABI

[Olivier Hainque]

> 
> 
> > The idea here could be to get a support for exception handling in various
> > languages without setjmp/longjmp. Perhaps would you have other suggestions
> > to achieve this on the PA ?
> Use the dwarf2 unwinder mechanism.  It's far better for this kind of thing.
> 

  Yes, agreed, but I thought that it was not supported by gcc on the PA 
  (typically missing some INCOMING_XXX macro things or alike).

  Olivier