RE: next emacs version?

[Drew Adams]

> > But sometimes (esp. if the release cycle is long) I do make 
> > changes (esp. if minor) that allow my code to keep working with the latest 
> > development version. That's sometimes easy when it concerns a
> > new var or fn (but not arity change etc. for a fn).
> 
> advice.el has code for figuring out the arg list of a 
> function, so you can check arity changes.  Though, the 
> easiest way may turn out to be loading advice and calling 
> ad-arglist....

No, I'm not going to go there. If I really have to deal with that, then I'm more
likely to use `condition-case' and try first the newer signature, backing out to
the older signature in case of error. (Obviously, that only works for some kinds
of changes.)