And we're finally polyfilling std::array to avoid writing these hack
structures over and over.
Unfortunately, we can't ever polyfill it *exactly* because Turbo C++
4.0J neither supports namespaces nor template classes nested inside
non-template classes to simulate namespaces. Might as well go for a
PascalCased class name in accordance with the existing coding style
then – no need to add an exception just to have a class name like
`std_array` or something.
Part of P0260, funded by Yanga.
nmlgc