[Bug libstdc++/66059] make_integer_sequence should use a log(N) implementation

[rhalbersma at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66059

--- Comment #2 from rhalbersma <rhalbersma at gmail dot com> ---
Apparently VC and Clang have compiler hooks for this:
https://www.reddit.com/r/cpp/comments/3t0nrc/true_story_efficient_packing_tales_of_c/cx26s02