[PATCH] support: Add TEST_COMPARE macro

[Paul Eggert]

On 11/27/2017 02:46 AM, Florian Weimer wrote:
>> #pragma GCC diagnostic ignored "-Wtype-limits"
>
> I don't think we want to use this throughout our test suite. 

Sure, but we can add it just for TEST_COMPARE, since -Wtype-limits is a 
false alarm and that is causing a hassle for this implementation.

Come to think of it, perhaps it would be easier to add -Wsign-compare 
only for TEST_COMPARE, and remove all the other gorp. What we're trying 
to do here, is to have the effect of -Wsign-compare. Surely it's better 
to do this check at compile-time with the compiler's help, rather than 
try to dodge the compiler and do the check at run-time.