IUSE="... vulkan" RDEPEND="... vulkan? ( media-libs/vulkan-loader )" GLFW supports Vulkan since version 3.2
I don't think there's anything to do here. It doesn't need anything at build time (relies on glad/), and will be able to use vulkan if it's available at runtime (through dlopen). Well, there's a build time option to link with static vulkan-loader but that's not something we want. At best could add a `optfeature "vulkan support"` but it feels kind of far-fetched to advertise given consumers also need to support vulkan through glfw and will likely work without it (and users will likely have it installed already if they want vulkan). Closing assuming I'm not overlooking anything.
