MS Visual Studio 2019 has builtin support for other compiler toolsets [1]. This commit adds support for compiling using LLVM/Clang 10 using Visual Studio. ClangCL pretends to be MSVC so the usual MSVC flags apply, see also [2]. For detecting if ClangCL is used, newer cmake verisons (>= 3.15) have builtin support using CMAKE_CXX_COMPILER_FRONTEND_VARIANT [3], for older ones a workaround is available using CMAKE_CXX_SIMULATE_ID [4]. [1]: https://devblogs.microsoft.com/cppblog/clang-llvm-support-in-visual-studio/ [2]: https://clang.llvm.org/docs/UsersManual.html#clang-cl [3]: https://stackoverflow.com/a/10055571 [4]: https://github.com/microsoft/CMake/commit/4fe34b2d29ca67ea91b2545b223dad8abbcad282
