задача собственно тривиальная, скачиваем, https://llvm.org/builds/ и устанавливаем добавляем PlatformToolsets на выбор, чем они отличаются, я не сравнивал
- https://github.com/zufuliu/llvm-utils или
- https://github.com/arves100/llvm-vs2017-integration
cmake .. -L -DCMAKE_INSTALL_PREFIX:PATH="../_Rel" -Wno-dev -DCMAKE_PREFIX_PATH="E:/tools/vcpkg/installed/x64-windows-static" -DCMAKE_CL_64=1 -DBUILD_TESTS:BOOL=OFF -G"Visual Studio 15 2017 Win64" -T"LLVM-vs2017" -DBUILD_SHARED_LIBS=OFF -DCMAKE_SYSTEM_VERSION=10.0.16299.0 cmake .. -L -DCMAKE_INSTALL_PREFIX:PATH="../_Rel" -Wno-dev -DCMAKE_PREFIX_PATH="E:/tools/vcpkg/installed/x64-windows-static" -DCMAKE_CL_64=1 -DBUILD_TESTS:BOOL=OFF -G"Visual Studio 15 2017 Win64" -T"LLVM v141" -DBUILD_SHARED_LIBS=OFF -DCMAKE_SYSTEM_VERSION=10.0.16299.0
cmake --build . --config Release -- /p:VcpkgTriplet="x64-windows-static"
msbuild /p:PlatformToolset="LLVM-vs2017" msbuild /p:PlatformToolset="LLVM v141"