These types of issues are now displayed in Xcode 9 as purple issues - more than warnings but less than fatal errors.
In conversations with people that have had some knowledge of decisions at Apple, it appears that they were originally going to make these hard errors, but it appears that Flurry has the same problem and Apple seemed to be unwilling to stop apps containing Flurry - just too many. As people move to Xcode 9 they will start seeing these warnings as well and have questions.
As this is a warning this should not crash the application. This issue has been identified and has been worked on. The fix is going to be available in v4.4.1.