win_macros.h Error

Hello,
I'm trying to compile my C4D plugin for R20, and I'm getting dozens of these error messages:

detect_win_macros.h(8): fatal error C1189: #error: GetMessage macro defined, you have to clean-up after a Windows include.
detect_win_macros.h(2): fatal error C1189: #error: INTERFACE macro defined, you have to clean-up after a Windows include.

Yes, I'm including <windows.h> in my source code files, because I'm using some Win32 functions.

I don't understand what "clean-up" means or what I have to do to fix it. Thanks.

I fixed the errors by adding this after every <windows.h> include:

#undef GetMessage
#undef INTERFACE
#undef CreateWindow
#undef GetObject
#undef AddJob
#undef GetClassInfo
#undef PASSTHROUGH
#undef SetPort

On to more error fixing.