Ignore clang warning Wnontrivial-memaccess (#8129, #8135)

Amend 88e2327
Use void* cast in backend where the memset are infrequent.

backends/imgui_impl_metal.mm

@@ -38,13 +38,6 @@
 #import <time.h>
 #import <Metal/Metal.h>
 
-#if defined(__clang__)
-#if __has_warning("-Wunknown-warning-option")
-#pragma clang diagnostic ignored "-Wunknown-warning-option"         // warning: unknown warning group 'xxx'
-#endif
-#pragma clang diagnostic ignored "-Wnontrivial-memaccess"           // warning: first argument in call to 'memset' is a pointer to non-trivially copyable type
-#endif
-
 #pragma mark - Support classes
 
 // A wrapper around a MTLBuffer object that knows the last time it was reused
@@ -83,7 +76,7 @@ - (MetalBuffer*)dequeueReusableBufferOfLength:(NSUInteger)length device:(id<MTLD
 {
     MetalContext*               SharedMetalContext;
 
-    ImGui_ImplMetal_Data()      { memset(this, 0, sizeof(*this)); }
+    ImGui_ImplMetal_Data()      { memset((void*)this, 0, sizeof(*this)); }
 };
 
 static ImGui_ImplMetal_Data*    ImGui_ImplMetal_GetBackendData()    { return ImGui::GetCurrentContext() ? (ImGui_ImplMetal_Data*)ImGui::GetIO().BackendRendererUserData : nullptr; }

backends/imgui_impl_osx.mm

@@ -27,13 +27,6 @@
 #import <GameController/GameController.h>
 #import <time.h>
 
-#if defined(__clang__)
-#if __has_warning("-Wunknown-warning-option")
-#pragma clang diagnostic ignored "-Wunknown-warning-option"         // warning: unknown warning group 'xxx'
-#endif
-#pragma clang diagnostic ignored "-Wnontrivial-memaccess"           // warning: first argument in call to 'memset' is a pointer to non-trivially copyable type
-#endif
-
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2024-08-22: moved some OS/backend related function pointers from ImGuiIO to ImGuiPlatformIO:
@@ -94,7 +87,7 @@
     id                          Monitor;
     NSWindow*                   Window;
 
-    ImGui_ImplOSX_Data()        { memset(this, 0, sizeof(*this)); }
+    ImGui_ImplOSX_Data()        { memset((void*)this, 0, sizeof(*this)); }
 };
 
 static ImGui_ImplOSX_Data*      ImGui_ImplOSX_GetBackendData()      { return (ImGui_ImplOSX_Data*)ImGui::GetIO().BackendPlatformUserData; }

backends/imgui_impl_vulkan.cpp

@@ -489,7 +489,7 @@ void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer comm
         wrb->Index = 0;
         wrb->Count = v->ImageCount;
         wrb->FrameRenderBuffers = (ImGui_ImplVulkan_FrameRenderBuffers*)IM_ALLOC(sizeof(ImGui_ImplVulkan_FrameRenderBuffers) * wrb->Count);
-        memset(wrb->FrameRenderBuffers, 0, sizeof(ImGui_ImplVulkan_FrameRenderBuffers) * wrb->Count);
+        memset((void*)wrb->FrameRenderBuffers, 0, sizeof(ImGui_ImplVulkan_FrameRenderBuffers) * wrb->Count);
     }
     IM_ASSERT(wrb->Count == v->ImageCount);
     wrb->Index = (wrb->Index + 1) % wrb->Count;
@@ -1445,8 +1445,8 @@ void ImGui_ImplVulkanH_CreateWindowSwapChain(VkPhysicalDevice physical_device, V
         wd->SemaphoreCount = wd->ImageCount + 1;
         wd->Frames = (ImGui_ImplVulkanH_Frame*)IM_ALLOC(sizeof(ImGui_ImplVulkanH_Frame) * wd->ImageCount);
         wd->FrameSemaphores = (ImGui_ImplVulkanH_FrameSemaphores*)IM_ALLOC(sizeof(ImGui_ImplVulkanH_FrameSemaphores) * wd->SemaphoreCount);
-        memset(wd->Frames, 0, sizeof(wd->Frames[0]) * wd->ImageCount);
-        memset(wd->FrameSemaphores, 0, sizeof(wd->FrameSemaphores[0]) * wd->SemaphoreCount);
+        memset((void*)wd->Frames, 0, sizeof(wd->Frames[0]) * wd->ImageCount);
+        memset((void*)wd->FrameSemaphores, 0, sizeof(wd->FrameSemaphores[0]) * wd->SemaphoreCount);
         for (uint32_t i = 0; i < wd->ImageCount; i++)
             wd->Frames[i].Backbuffer = backbuffers[i];
     }

imgui.cpp

@@ -1135,6 +1135,7 @@ CODE
 #pragma clang diagnostic ignored "-Wdouble-promotion"               // warning: implicit conversion from 'float' to 'double' when passing argument to function  // using printf() is a misery with this as C++ va_arg ellipsis changes float to double.
 #pragma clang diagnostic ignored "-Wimplicit-int-float-conversion"  // warning: implicit conversion from 'xxx' to 'float' may lose precision
 #pragma clang diagnostic ignored "-Wunsafe-buffer-usage"            // warning: 'xxx' is an unsafe pointer used for buffer access
+#pragma clang diagnostic ignored "-Wnontrivial-memaccess"           // warning: first argument in call to 'memset' is a pointer to non-trivially copyable type
 #elif defined(__GNUC__)
 // We disable -Wpragmas because GCC doesn't provide a has_warning equivalent and some forks/patches may not follow the warning/version association.
 #pragma GCC diagnostic ignored "-Wpragmas"                          // warning: unknown option after '#pragma GCC diagnostic' kind

imgui.h

@@ -135,6 +135,7 @@ Index of this file:
 #pragma clang diagnostic ignored "-Wzero-as-null-pointer-constant"  // warning: zero as null pointer constant
 #pragma clang diagnostic ignored "-Wreserved-identifier"            // warning: identifier '_Xxx' is reserved because it starts with '_' followed by a capital letter
 #pragma clang diagnostic ignored "-Wunsafe-buffer-usage"            // warning: 'xxx' is an unsafe pointer used for buffer access
+#pragma clang diagnostic ignored "-Wnontrivial-memaccess"           // warning: first argument in call to 'memset' is a pointer to non-trivially copyable type
 #elif defined(__GNUC__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wpragmas"                          // warning: unknown option after '#pragma GCC diagnostic' kind

imgui_tables.cpp

@@ -229,6 +229,7 @@ Index of this file:
 #pragma clang diagnostic ignored "-Wdeprecated-enum-enum-conversion"// warning: bitwise operation between different enumeration types ('XXXFlags_' and 'XXXFlagsPrivate_') is deprecated
 #pragma clang diagnostic ignored "-Wimplicit-int-float-conversion"  // warning: implicit conversion from 'xxx' to 'float' may lose precision
 #pragma clang diagnostic ignored "-Wunsafe-buffer-usage"            // warning: 'xxx' is an unsafe pointer used for buffer access
+#pragma clang diagnostic ignored "-Wnontrivial-memaccess"           // warning: first argument in call to 'memset' is a pointer to non-trivially copyable type
 #elif defined(__GNUC__)
 #pragma GCC diagnostic ignored "-Wpragmas"                          // warning: unknown option after '#pragma GCC diagnostic' kind
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"                // warning: format not a string literal, format string not checked

imgui_widgets.cpp

@@ -79,6 +79,7 @@ Index of this file:
 #pragma clang diagnostic ignored "-Wdeprecated-enum-enum-conversion"// warning: bitwise operation between different enumeration types ('XXXFlags_' and 'XXXFlagsPrivate_') is deprecated
 #pragma clang diagnostic ignored "-Wimplicit-int-float-conversion"  // warning: implicit conversion from 'xxx' to 'float' may lose precision
 #pragma clang diagnostic ignored "-Wunsafe-buffer-usage"            // warning: 'xxx' is an unsafe pointer used for buffer access
+#pragma clang diagnostic ignored "-Wnontrivial-memaccess"           // warning: first argument in call to 'memset' is a pointer to non-trivially copyable type
 #elif defined(__GNUC__)
 #pragma GCC diagnostic ignored "-Wpragmas"                          // warning: unknown option after '#pragma GCC diagnostic' kind
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"                // warning: format not a string literal, format string not checked