Jason Rhinelander f1b44a051a <optional> requires -std=c++17 (#479) ... There are now more places than just descr.h that make use of these. The new macro isn't quite the same: the old one only tested for a couple features, while the new one checks for the __cplusplus version (but doesn't even try to enable C++14 for MSVC/ICC). g++ 7 adds <optional>, but including it in C++14 mode isn't allowed (just as including <experimental/optional> isn't allowed in C++11 mode). (This wasn't triggered in g++-6 because it doesn't provide <optional> yet.)		2016-11-04 14:49:37 +01:00
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pybind11	<optional> requires -std=c++17 (#479)	2016-11-04 14:49:37 +01:00