Issue an internal warning on first deprecated function call

[Carlos O'Donell]

> > 
> > What's wrong with making users scared?
> 
> It's wrong because GDB users cannot do anything about the problem, and
> the message's language seems to imply it's a potentially very grave
> problem (which it isn't).
> 

It's not a grave problem? Please explain.

> > What if there are no port maintainers?
> Then the head maintainer gets the honor.

Like the parisc port?

c.