Can I ask you about Runtime\Public\HAL\Platform.h's macro?

(Sorry for my poor English first of all.)
HAL\Platform.h has a lot of definitions. some examples

#if !defined(PLATFORM_WINDOWS)
#define PLATFORM_WINDOWS 0
#endif
#if !defined(PLATFORM_XBOXONE)
#define PLATFORM_XBOXONE 0
#endif

But, I am really confused that “HAL\Platform.h” only include “Misc\Build.h”,
but “Misc/Build.h” doesn’t own Platform definition macro.

Could you tell me how to c++ project file(.vcxproj) determine Macro of “HAL\Platform.h” and “Misc\Build.h”?

Thank you for reading this!