[Bug libstdc++/88466] [C++17] Support std::hardware_destructive_interference_size and std:: hardware_constructive_interference_size

[duarte at scylladb dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88466

--- Comment #2 from Duarte <duarte at scylladb dot com> ---
I don't think it should be the min size. For example, architectures with 64bit
cache lines can have prefetchers that immediately fetch adjacent cache lines,
in which case the value should be 128.

One option could be to just use whatever values linux uses :)