Here's a patch that applies on top of the other two.  I think
it's easy to read it split out from the other patches.

This handles the layout conversion for x86/amd64, near the
PTRACE_[G|S]ETSIGINFO calls, like we discussed yesterday.

I'm not adjusting gdbserver here yet, since the original series
added $_siginfo support for ARM, and x86/amd64 only, and, gdbserver
on x86/amd64 isn't biarch aware yet.  We can handle doing something
like this there when we add $_siginfo gdbarch type support for ppc, or
when we add biarch support for x86/amd64.

What do you think?  I've tried to make it as pretty as I could.  :-)

Please, don't hesitate pointing me at anything bogus I may
be doing.

-- 
Pedro Alves