[boost] additional math-functions

Hello, I would like to add several missing math functions in boost or specialize/overload existing ones for more types. These should be constexpr if possible. My problems with the concrete implementations are: - Which C++ standard to use C++11/14/17/20/23 ? - Should these be implemented in ccmath and math ? a) ccmath requires C++17 (eg "if constexpr"), so it is not possible to simply call the ccmath version in math, since math requires C++11. b) On the other hand, the math functions are already included in the standard (since C++11), so it wouldn't be necessary to continue to provide them (especially since they are not constexpr). Where and how exactly and with which C++ standard can I add the functions ? thx Gero