836addcbc4
If the target we're generating code for is msvc, then we do two main things differently: we generate type names in a C++ style instead of a Rust style and we generate debuginfo for enums differently. I've refactored the code so that there is one function (`cpp_like_debuginfo`) which determines if we should use the C++ style of naming types and other debuginfo generation or the regular Rust one.
Please read the rustc-dev-guide chapter on Backend Agnostic Codegen.