New "info auxv" command and $auxv variable?

[Andrew Cagney]

> But why stop there?  What about a builtin $auxv variable, a struct, vis:
>> 
>> 	(gdb) print $auxv
>> 	$1 = { entry = 0x1234, ... }
>> 
>> Oh, and I guess:
>> 
>> 	(gdb) interpreter mi --info-auxv
>> 	^ok,result={entry="0x1234",...}
>> 
>> Thoughts?
> 
> 
> I don't know if there's enough utility to bother doing this, though...
> the only thing likely to be generally useful is the entry point (and
> maybe the vsyscall address).

If we start making the CLI more usable by making this stuff available 
people might start using it :-)

Anyway, the MI stuff is almost free (the code is common).  The $auxv 
variable is a bit tricky but still ok.  Could just add $entrypoint?

Andrew