To avoid taking a dependency on ffmpeg 5.1 before we're ready (we need
a newer Ubuntu LTS release to drop ffmpeg 4.x support), ut not force us
to wait to add support for picking Vulkan devices by UUID, I'm copying
the uuid code from ffmpeg into mpv. It's one file with no private
dependencies, so it's easier to copy than to reimplement in any other
way.
Licence is LGPL so matches us.
Philip Langdale