Correctly include windows.h with necessary macros defined so that the set of symbols we need get declared. This header file purposly does nothing on non-Windows platforms.

If you get strange compilation errors on Windows only the easiest fix is to insert the inclusion of this file at the very start of your source file. The likely problem is that some other header file is including windows.h.

Please do not include this file unless windows.h is absolutely necessary. It pollutes the namespace with lots of unwanted symbols and makes portability of the resulting source very difficult.