Comment by mikekchar

Kind of late to the game here, but MS could ship actual source code and copying that code would still be copyright infringement. Reverse engineering for inter-operability is legal in many places, but copying implementations is not. Even having seen the code, you would have to reimplement it in a way that worked equivalently, but was different. The OP is claiming that even things like macros have the same implementation and names (i.e. code that is never exposed publicly in any way). Even if you could deduce this from debug symbols (which would be quite tricky, but probably not impossible), you've got to find another way to do that work.

I don't really subscribe to a belief of absolute morality, but in the context of the discussion, I think that no matter how you got access to that code, if you say that you are reverse engineering it, then copying an implementation is not doing what you are saying you are doing (as well as being copyright infringement).