* Bump API patch number and header version number to 63 for this update.
Github Issues:
* Add missing valid usage statements for ptext:maxDescriptorSets*,
ptext:maxPerStageDescriptorInputAttachments, and
ptext:maxPerStageResources to slink:VkPipelineLayoutCreateInfo.txt,
flink:VkComputePipelineCreateInfo, and
flink:VkGraphicsPipelineCreateInfo (public issue 546).
* Fix typos in ftext:vkCmdDraw*AMD descriptions (public pull request 549).
* Fixed flink:vkCmdWriteTimestamp so it is not unnecessarily restricted to
queues supporting graphics or compute operations (public issue 558).
* Improvements to valid usage generator for output `*Flags` pointer
parameters and for some `void *` parameters (public pull requests 560,
562).
* Document `altlen` attribute in XML schema as valid C99 syntax and tweak
`vk.xml` to match (public pull request 566).
* Clarify when pname:fence is signaled by flink:vkQueueSubmit in a more
obvious place (public issue 577).
Internal Issues:
* Specify a whitelist of supported SPIR-V Storage Classes in the
<<spirvenv-module-validation, Validation Rules within a Module>>
appendix (internal SPIR-V issue 166).
* Relax the shared semaphore wait timeout requirement in the
<<synchronization-semaphores-importing, Importing Semaphore Payloads>>
section (internal issue 820).
* Update the <<textures-image-level-selection, Image Level(s) Selection>>
equations so that the parameters returned by the level-of-detail query
appear explicitly, also fixing the issue that linear filtering would
select a level below the base level for magnification (internal issue
926).
* Disallow creation of a swapchain with zero pname:imageExtent in
slink:VkSurfaceCapabilitiesKHR and slink:VkSwapchainCreateInfoKHR
(internal issue 1020).
Other Issues:
* Clarify in <<textures-operation-validation,Image View Validation>> that
the layout of subresources in an image view must have a layout that
matches that written into the descriptor, and that this section is about
validating image views, not images.
New Extensions:
* `VK_EXT_global_priority`
Jon Leech