funPtrToAddr and addrToFunPtr

[Alastair Reid]

> Well, we don't like to encourage the use of deprecated APIs, and I
> had intended to remove it for the next major release (it's been
> deprecated for well over 12 months).  Do you still need Addr for
> something?

Old Greencard interfaces use it.  In fact, I don't think we've added
Ptr and FunPtr support to the StdDIS.gc files yet so even shiny new
greencard interfaces will use it

For now I'm casting the funptr to a ptr and then casting that to addr.

A