backend (Vulkan): Fix struct compatibility

For platforms not supporting 1.3 and dynamic rendering, the init info
struct does not include the VkPipelineRenderingCreateInfoKHR.
Easiest solution for now is to ensure the structure is consistent by
adding a bogus structure which matches VkPipelineRenderingCreateInfoKHR
exactly.

Author: nfginola

libs/imgui/backends/imgui_impl_vulkan.h

@@ -64,6 +64,17 @@
 #define IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
 #endif
 
+// FIX(zig-gamedev) - Match PipelineRenderingCreateInfo structure for compatibility
+typedef struct unusedVkPipelineRenderingCreateInfo {
+    uint32_t           sType;
+    const void*        pNext;
+    uint32_t           viewMask;
+    uint32_t           colorAttachmentCount;
+    const uint32_t*    pColorAttachmentFormats;
+    uint32_t           depthAttachmentFormat;
+    uint32_t           stencilAttachmentFormat;
+} unusedVkPipelineRenderingCreateInfo;
+
 // Initialization data, for ImGui_ImplVulkan_Init()
 // - VkDescriptorPool should be created with VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT,
 //   and must contain a pool size large enough to hold an ImGui VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER descriptor.
@@ -91,6 +102,8 @@ struct ImGui_ImplVulkan_InitInfo
     bool                            UseDynamicRendering;
 #ifdef IMGUI_IMPL_VULKAN_HAS_DYNAMIC_RENDERING
     VkPipelineRenderingCreateInfoKHR PipelineRenderingCreateInfo;
+#else
+    unusedVkPipelineRenderingCreateInfo PipelineRenderingCreateInfo;
 #endif
 
     // (Optional) Allocation, Debugging