windows.h adds macros such as `#define GetMessage GetMessageA` which
cause conflicts in naming when for example a class definition is before
windows.h and a use is after windows.h
Add a header that can be used both to include windows.h and remove
defines, and to only remove defines (when windows.h is included by)
external dependencies.
This file changes the non-dispatchable Vulkan handle types. We want to
use some of these handles in utils/VulkanSwapChain.cpp so it needs to
have access to it. The file could include
backend/vulkan/vulkan_platform.h but it seems a bit cleaner to move the
header in common/ instead with a warning if the Vulkan backend isn't
enabled.
Corentin Wallez