Adds initial support for VK_KHR_wayland_surface.
Very basic Wayland support is implemented by importing memory with VK_EXT_image_drm_format_modifiers. The current implementation requires an external system memory allocator. An API for this allocator is defined in util/wsialloc/wsialloc.h and an implementation using the ION memory allocator is included. Outstanding issues: * This is an initial prototype for Wayland support and has many outstanding TODOs which need addressing to properly use the Wayland protocol. * Using ICD Exported memory instead of a system allocator is not implemented. Wayland support is still experimental and outstanding issues will be fixed in future commits. Change-Id: I1b0d5991e15ff1cf25ebbab3392a631b021e8c17 Signed-off-by: Rosen Zhelev <email@example.com> Signed-off-by: Iason Paraskevopoulos <firstname.lastname@example.org>