[Development] Houston, qint128 has a problem

[Karl Semich]

Comment from peanut gallery,

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40856

> This code should produce the same results with -std=g++11 and -std=c++11

> I will not object to patches tweaking the condition and positively reviewed by fellow maintainers.

It sounds like the GCC maintainers (12 years ago) would have been
conducive to making the two modes consistent, but nobody pushed the
change through.

Given in strict mode the template is simply not specialized, it could
make sense to simply specialize any missing template values. Similar
to specializing for user-defined types.