[patch] convert some call ABI macros to hooks, apply to sh, add bitfield swapper

[DJ Delorie]

> I'm going through the SH-specific changes only.  I have only cosmetic
> changes to request, assuming the changes from macro to functions were
> only mechanical, such that I don't have to check that the logic is
> unchanged.  Is this the case?  If not, could you please highlight the
> changes (maybe even submit them separately, if it's not too
> difficult)?  Thanks,

Sorry, there were logic changes.  I wouldn't have gone through all
that just for cosmetics ;-)

I'm hoping I'll hear from the folks who need to approve the front-end
changes shortly, in case they ask for changes that require back-end
changes also.

I fear I'll have to break this patch up into a zillion little patches
just to get people to look at it :-P