Incorrect check: "MSVC doesn't support C++1x"

[TheJoYo]

None of these ELSEIF ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC") checks are actually checking if MSVC supports that dialect.

Example of this invalid check here

In this example, Visual Studio 2019 fails to build because of this check despite supporting C++17

[ygj6]

Yes, MSVC now also supports C++17. See Visual Studio 2017 15.7 Brings Full C++17 Compliance and Microsoft C++ language conformance table. But here still needs some testing.