[All] Fixed multiple issues during build on Linux

- Added some fixes introduced by RodoMa92 in PR198

- Lack of AVX2 extension (should be done differently in the future)
- Disable deprecated-volatile warning
- Added missing override in posix EventInfo, ImGui notification class and XContent class
- Removed not used XAudio2.h include in XMP
- Fixed missing switch-case in XObject
- Added fugly template in native_list.h
- Fixed multiple smaller issues

src/xenia/ui/imgui_host_notification.cc

@@ -79,9 +79,9 @@ void HostNotificationWindow::OnDraw(ImGuiIO& io) {
   {
     ImGui::SetWindowFontScale(window_scale);
 
-    ImGui::Text(GetTitle().c_str());
+    ImGui::Text("%s", GetTitle().c_str());
     ImGui::Separator();
-    ImGui::Text(GetDescription().c_str());
+    ImGui::Text("%s", GetDescription().c_str());
   }
   ImGui::End();
 }