boring-sys compile failed on windows

[Lsyx-Good]

boring-sys compile failed when set env CMAKE_GENERATOR = Ninja , crypto library exist on compiler output path, but search library path is incorrect, for msvc targets it adds debug/RelWithDebInfo/Release to the library path, which is wrong for CMAKE_GENERATOR as Ninja.

[PaulDance]

This is what #223 aims to fix, although it probably needs to be updated. It's at least a good sign that it does not happen only to us.