Exception handling

[Jim Dehnert]

I've updated the EH specification based on last week's meeting.
In addition to a variety of minor items, there are a couple of substantive
areas of change that you should look at.  I've tried to identify them
with a red font in the HTML (PDF is not yet updated).

  - I've added a unified list of reason codes, with the _Unwind prefix,
    and referenced it in multiple places, including the throw routines.
    In particular, I've used its type in several places instead of int
    and uint64 -- we need to identify the right type.

  - I've cleaned up the _Unwind_ForcedUnwind definition.

Please take a close look.  We'll talk about it Thursday.

Jim

-	    Jim Dehnert		dehnert at sgi.com
				(650)933-4272