gcc conformance to HP-PA ABI

[Richard Kenner]

    I should think that the overhead of the HP unwind library would be
    higher than the overhead of setjmp/longjmp.

Do you mean overhead when an exception *occurs* or in going into a region
with an exception handler?

setjmp/longjmp is very efficient for handling the exception, but
extremely inefficient in programs where the exceptio doesn't occur
(the main cost is that the location of the setjmp buffer is
thread-specific data).