Issue an internal warning on first deprecated function call

[Andrew Cagney]

>> > 
>> > 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.

Eli's right here.  The warning would be to strong.

internal-error and internal-warning refer to GDB detecting an errenous 
internal state.  Error for non-recoverable, warning for recoverable.

Unless some action is taken, the long term prognosis doesn't look good. 
  However, short term, GDB could just as easily die due to a SIGSEG.

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

Yep.  I get to ``fix'' the problem.

I just checked in a change to MAINTAINERS file so that it recommends 
hppa-elf as the target to try building.  This new target doesn't include 
som support (unlike hppa natives) and so makes the multi-arch task just 
that bit more feasible :-)

enjoy,
Andrew