boost's cmake config files are not compatible with clang-cl

On Windows, clang-cl is compatible for compiling and linking against MSVC libraries.
In this case with MSVC compiled boost. Therefore, the cmake-config file should not report "NOTFOUND" if I actually want MSVC compiled boost libraries to be linked. Boost should also generally detect if clang is running in compatibility mode for msvc and simulate a build as with msvc as well.