An attempt at Vulkan

The Vulkan backend is basically done. Currently, I’m looking for some advice on how to handle compatibility with OpenGL GLSL shaders. The backend can already accept Vulkan GLSL code directly. Should I keep defining the Vulkan GLSL sections within the existing shader macros, or is there a better tool that can write shaders and output both OpenGL GLSL and Vulkan GLSL? If you have any ideas, feel free to share them here.