Here is a newer version of the patch that does not use _HAS_CXX17, as it should not really be relied upon ( https://stackoverflow.com/questions/52379233/is-has-cxx17-marco-usable-in-custom-project-headers-to-enable-c17-language).
I think the right way will be using only standard-compliant "__cplusplus" in sources and adding the option "/Zc:__cplusplus" for MSVC compiler in the build scripts so it handle __cplusplus in standard-compliant way:
https://docs.microsoft.com/en-us/cpp/build/reference/zc-cplusplus?view=msvc-160 Yuriy -- lyx-devel mailing list lyx-devel@lists.lyx.org http://lists.lyx.org/mailman/listinfo/lyx-devel
