Now we can provide Vulkan support in the build even if the build box doesn't
have a Vulkan SDK, since we dynamically link to the library anyhow.
--HG--
extra : rebase_source : f4972489a15b276f65ea65c077172fdcbbe3420a
This work was done by Jacob Lifshay and Mark Callow; I'm just merging it
into revision control.
--HG--
extra : rebase_source : cb3bb332146125366b5242c0d7444f44638733d9
extra : amend_source : c72ebb6d3a92efc3fdd085ce3b6d4b1d7f573cc9