[PATCH] Add C++ versions of iscanonical for ldbl-96 and ldbl-128ibm

[Gabriel F. T. Gomes]

On 03 Oct 2017, Joseph Myers wrote:

>> +/* In C++ mode, __MATH_TG cannot be used, because it relies on
>> +   __builtin_types_compatible_p, which is a C-only builtin.  On the
>> +   other hand, overloading provides the means to distinguish between
>> +   the floating-point types.  The overloading resolution will match
>> +   the correct parameter (regardless of type qualifiers (i.e.: const
>> +   and volatile).  */  
>
>(twice in this patch, and once already in math.h) is missing a second 
>close parenthesis to match the first open parenthesis, and should be 
>fixed.

Thanks.  Pushed with these changes.