[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_guest_notification.cc

@@ -170,7 +170,7 @@ void AchievementNotificationWindow::OnDraw(ImGuiIO& io) {
 
     ImGui::SameLine();
     if (notification_draw_progress_ > 0.5f) {
-      ImGui::TextColored(white_color, GetNotificationText().c_str());
+      ImGui::TextColored(white_color, "%s", GetNotificationText().c_str());
     }
   }
   // Restore previous style
@@ -248,7 +248,7 @@ void XNotifyWindow::OnDraw(ImGuiIO& io) {
 
     ImGui::SameLine();
     if (notification_draw_progress_ > 0.5f) {
-      ImGui::TextColored(white_color, GetDescription().c_str());
+      ImGui::TextColored(white_color, "%s", GetDescription().c_str());
     }
   }
   // Restore previous style