WIP: comp: Add VK_LAYER_KHRONOS_validation layer.
On recent Vulkan installations the VK_LAYER_LUNARG_standard_validation
layer does not output anything, even though it is in place.
Adding the new Khronos layer and leaving the old one for compatibility.
This must be tested on a Vulkan installation with the VK_LAYER_KHRONOS_validation
not available!
We currently do not check if the validation layers we enable are available, but that may not be necessary.
Otherwise we will need something like this, as seen in xrdesktop: https://gitlab.freedesktop.org/xrdesktop/gulkan/blob/master/src/gulkan-instance.c#L143