Limit the scope of #include <windows.h>

Background: I want to enable NVIDIA optimus by default. The solution recommended by NVIDIA is to use extern "C" _declspec(dllexport) DWORD NvOptimusEnablement = 0x00000001;.

Therefore I need DWORDto be defined.

I have read this question which asks for the minimum header that defines DWORD with the best solution being to define WIN32_LEAN_AND_MEAN and still use windows.h or to define it yourself because it is unlikely to change.

In contrast to the mentioned question I have no problem with the size of windows.h in itself (none issue when using precompiled headers). I would however like to avoid to clutter the global namespace with all its types, functions etc. especially since I only need one type for one line of code.

TLDR: Is there any way to include the header but have all of its content only available in a limited scope?

Note that you can't simply include the header in a namespace like so:

namespace encloseWindowsTypes {
  #include <Windows.h>
  extern "C" _declspec(dllexport) DWORD NvOptimusEnablement = 0x00000001;
}

since part of the windows.h relies on previous part of it being defined in global namespace and you would get errors like 'div_t': is not a member of '`global namespace''.