PPC startup code

[Paul Mackerras]

Roland McGrath writes:

> In fact, I don't mind doing all this cleanup in libc-start.c myself.
> Someone just has to decide about whether start.S and the calling sequence
> ought to change or stay the same.  I vote for changing it to match every
> other platform.  But I don't speak for powerpc users.

Given that the calling sequence is in fact defined in the ABI spec, I
think we probably shouldn't change it without a really good reason.
It would be good to use the generic __libc_start_main code, though,
by having the PPC __libc_start_main be a small shim that calls the
generic one (presumably renamed to __generic_libc_start_main or
something).  But I guess it is ultimately up to Franz to decide.

Paul.