layers: Copy json config files to build directory
layers: Copy json config files to build directory

JSON library_path field should contain relative
path to the layer library. Easiest if both json and
library file live in the same spot.

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools