@woof fun as `cmath` stuff in C++11 is not constexpr compatible from the spec, so the code would only work under gcc.

https://stackoverflow.com/questions/17347935/constexpr-math-functions

also, under C++11 all `constexpr` functions need to directly return a value without any variables or making use of loops, which the code clearly makes use of.

C++14 and beyond supposedly alleviates this but the silly bot specifically mentioned C++11.