title: How to choose specific GPU when create OpenGL context
body: <p>On my MS Surface3 laptop in my app i'm using SDL2 and trying to create OpenGL context.
  During creation it always using integrated intel GPU instead of NVidia. And I have no idea how to choose discrete GPU.
  I googled entire day today, but there just some info about choosing it via Optimus?
  I duno what is this, i don't have any Optimus settings on my laptop. And anyway really need to choose GPU programmatically, not using Control Panel.
  Is it really no way to choose GPU using OpenGL API ?</p>
  <p>I have another app, which is using DirectX 11. And I can easily choose GPU there by simple enumeration. So NVidia GPU is definitely available on my Laptop. I just don't know how to select it using OpenGL.</p>