tree 59260cd4404789136cd33baa4c31876c42a8dd7a
parent d15b217f1abc1b9bf8bdc904772175bee6d6c77e
author Jason Rhinelander <jason@imaginary.ca> 1494354885 -0400
committer Jason Rhinelander <jason@imaginary.ca> 1494362507 -0400

Update PYBIND11_CPP1{4,7} macros for MSVC

The PYBIND11_CPP14 macro started out as a guard for the compile-time
path code in `descr.h`, but has since come to mean other things.  This
means that while the `descr.h` check has just checked the
`PYBIND11_CPP14` macro, various other places now check `PYBIND11_CPP14
|| _MSC_VER`.  This reverses that by now setting the CPP14 macro when
MSVC is trying to support C++14, but disabling the `descr.h` C++14 code
(which still fails under MSVC 2017).

The CPP17 macro also gets enabled when MSVC 2017 is compiling with
/std:c++latest (the default is /std:c++14), which enables
`std::optional` and `std::variant` support under MSVC.