PATCH: Various GC fixes

[Bryce McKinlay]

Boehm, Hans wrote:

>I'm not sure whether the following is appropriate for the trunk at this
>stage.  This patch was originally motivated by Andreas Tobler's work
>on porting gcj to HP/UX.  But in that process I also compared the gcc
>"boehm-gc" tree to the current upstream tree, looking for any important
>patches that hadn't made it.  I'm open to checking in only parts of
>this, if that's the wish.
>
>I'm doing more testing, but it passed initial tests on IA64.  Much, though
>not all, of this is in GC6.4.  (I did not include GC6.4 changes which I
>did not think would affect basic correctness on already supported platforms.)
>All of it is in my current upstream tree.
>
>OK for trunk?
>  
>

This patch sounds quite reasonable to me. If you're satisfied that it 
test out ok, please go ahead and check it in.

Regards

Bryce