V3 PATCH: numeric_limits<> support, fix PR/3865

[Gabriel Dos Reis]

Neil Booth <neil@daikokuya.co.uk> writes:

| Gabriel Dos Reis wrote:-
| 
| > Now, C++ rules require
| > 
| >      L'\0' - 1
| > 
| > be evaluated after "the usual arithmetic conversions are performed".
| 
| Hmm, you're right.  I guess that no test of this kind works properly
| in all cases, right?

Yes.

I remember the time I wrote a tiny program to compute the numerical
limits thingy -- it ran through all kinds of non-portability 
problems.  And if we're now using predefined macro based approach
(which I think is far better than what we previously did), it is
because I looked for alternatives and this one seems to be much more
reliable and scalable. 

-- Gaby