Create a version of the GLSL spec with GL_KHR_vulkan_glsl integrated?

Using GLSL with Vulkan requires checking both the GLSL spec and then verifying with the GL_KHR_vulkan_glsl extension what is available. Would it be possible to create a new version of the GLSL spec (maybe with a different name like was done for ESSL?) that directly integrates the Vulkan extensions and removes anything which is not usable from Vulkan?

I don't know how invasive the Vulkan changes would be to the spec if they could be done with the current `ifdef` mechanism or not?

Start by comparing the GLSL spec with the GL_KHR_vulkan_glsl extension, then investigate whether the existing ifdef mechanism can express the requested Vulkan-specific version. Done would be a defined proposal for a separately named spec with Vulkan-incompatible features removed or integrated.

Written by the indexing model from the issue text.