https://github.com/KhronosGroup/Vulkan-Headers
Arch can be a little slow on updating these, and AUR -git packages are incomplete, preventing us to build VKD3D using them. So here we go.
git clone https://github.com/Frogging-Family/vulkan-headers-git.git
cd vulkan-headers-git
makepkg -si