constexpr math functions

[lefticus]

https://github.com/kthohr/gcem

Note: this is available on compiler-explorer too

• It's C++11 - so lots of recursion
• If you were making a C++20 fork of it, you'd probably want make these consteval to force compile time evaluation?

[fcolecumberri]

It might also be interesting to mention

https://en.cppreference.com/w/cpp/numeric/constants

When people say C++ is going too fast, just remember, they took 40 years to add e, π.

[lefticus]

Coming in Ep449