Update change log for 1.0.23.

ChangeLog.txt

@@ -1081,3 +1081,61 @@ Other Commits:
     list for generator into the script arguments instead of the body of
     genvk.py, and express better dependencies between XML, scripts, and
     generated files.
+
+-----------------------------------------------------
+
+Change log for August 5, 2016 Vulkan 1.0.23 spec update:
+
+  * Bump API patch number and header version number to 23 for this update.
+
+Github Issues:
+
+  * Add explicit valid value attributes to pname:sType members in vk.xml
+    (public issue 34).
+  * Clarify usage of flink:vkGetInstanceProcAddr and
+    flink:vkGetDeviceProcAddr (public issue 225).
+  * Fix a copy-and-paste error in the description of
+    pname:pSwapchainImageCount saying that it was the count of ``format
+    pairs'' instead of ``swapchain images'' (public issue 292).
+  * flink:vkCmdExecuteCommandBuffers requires all command buffers to be
+    allocated from command pools created for the same queue family (public
+    issue 296).
+  * Remove bogus +optional+ attribute for
+    flink:vkEnumerateDeviceLayerProperties::pname:physicalDevice from vk.xml
+    (public issue 301).
+  * Clean up the <<resources-image-views-compatibility,image and image view
+    compatibility table>> reference and contents. Use full enumerant names.
+    Refer to pname:layerCount in the ``view parameters'' column instead of
+    pname:arrayLayers. Require N >= 1 for the cube array subview row, not
+    just arrayLayers >= 6 N (public issue 304).
+  * Modify description of <<resources-memory-aliasing,memory aliasing>> to
+    be consistent with the description of
+    <<resources-bufferimagegranularity,buffer image granularity>> (public
+    issue 307).
+
+Internal Issues:
+
+  * Describe remaining +vk_platform.h+ macros in the <<boilerplate,API
+    Boilerplate>> appendix (internal issue 6).
+  * Clarify
+    <<features-features-robustBufferAccess,pname:robustBufferAccess>>
+    feature behavior; what memory can be accessed, how bounds checking is
+    performed, and allowing for vectorization (internal issue 332).
+  * Document markup for automatic extraction of reference pages from the
+    spec sources in the style guide (internal issue 395).
+  * Allow flink:vkCreateDisplayModeKHR to return
+    ename:VK_ERROR_INITIALIZAION_FAILED_KHR if the user requests mode
+    parameters that the specified display does not support (internal issue
+    411).
+  * Remove atomic counters (atomic_uint style) from KHR_vulkan_glsl, and
+    more clearly remove the subroutine keyword alongside it (internal issue
+    421).
+  * Clarify behavior of flink:vkCmdBindDescriptorSets for descriptor sets
+    not contained in the layout (internal issue 427).
+
+Other Commits:
+
+  * Change the order in which members of sname:VkAttachmentDescription and
+    sname:VkPipelineInputAssemblyStateCreateInfo are described to match
+    their order in the structures.
+