Viewports: SDL2: Honor NoTaskBarIcon flag under non Win32 OS. (#2117)

examples/imgui_impl_sdl.cpp

@@ -467,6 +467,10 @@ static void ImGui_ImplSDL2_CreateWindow(ImGuiViewport* viewport)
     sdl_flags |= SDL_WINDOW_HIDDEN;
     sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? SDL_WINDOW_BORDERLESS : 0;
     sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoDecoration) ? 0 : SDL_WINDOW_RESIZABLE;
+#if !defined(_WIN32)
+    // See SDL hack in ImGui_ImplSDL2_ShowWindow().
+    sdl_flags |= (viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon) ? SDL_WINDOW_SKIP_TASKBAR : 0;
+#endif
 #if SDL_HAS_ALWAYS_ON_TOP
     sdl_flags |= (viewport->Flags & ImGuiViewportFlags_TopMost) ? SDL_WINDOW_ALWAYS_ON_TOP : 0;
 #endif