Backends: further zealous warning fixes. (#9247)

backends/imgui_impl_dx12.h

@@ -24,6 +24,12 @@
 #include <dxgiformat.h> // DXGI_FORMAT
 #include <d3d12.h>      // D3D12_CPU_DESCRIPTOR_HANDLE
 
+// Clang/GCC warnings with -Weverything
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wold-style-cast" // warning: use of old-style cast
+#endif
+
 // Initialization data, for ImGui_ImplDX12_Init()
 struct ImGui_ImplDX12_InitInfo
 {
@@ -76,4 +82,8 @@ struct ImGui_ImplDX12_RenderState
     ID3D12GraphicsCommandList*  CommandList;
 };
 
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_vulkan.cpp

@@ -116,6 +116,14 @@
 #pragma warning (disable: 4127) // condition expression is constant
 #endif
 
+// Clang/GCC warnings with -Weverything
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Wold-style-cast"                 // warning: use of old-style cast
+#pragma clang diagnostic ignored "-Wsign-conversion"                // warning: implicit conversion changes signedness
+#pragma clang diagnostic ignored "-Wimplicit-int-float-conversion"  // warning: implicit conversion from 'xxx' to 'float' may lose precision
+#pragma clang diagnostic ignored "-Wcast-function-type"             // warning: cast between incompatible function types (for loader)
+#endif
+
 // Forward Declarations
 struct ImGui_ImplVulkan_FrameRenderBuffers;
 struct ImGui_ImplVulkan_WindowRenderBuffers;

backends/imgui_impl_vulkan.h

@@ -50,6 +50,12 @@
 //#define IMGUI_IMPL_VULKAN_VOLK_FILENAME    <volk.h>       // Default
 // Reminder: make those changes in your imconfig.h file, not here!
 
+// Clang/GCC warnings with -Weverything
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wold-style-cast" // warning: use of old-style cast
+#endif
+
 #if defined(IMGUI_IMPL_VULKAN_NO_PROTOTYPES) && !defined(VK_NO_PROTOTYPES)
 #define VK_NO_PROTOTYPES
 #endif
@@ -261,4 +267,8 @@ struct ImGui_ImplVulkanH_Window
     }
 };
 
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+
 #endif // #ifndef IMGUI_DISABLE