I am coding an iOS 8 app in swift using the FBSDK to allow users to log in to my app. So far I have successfully implemented the login feature using the FBSDK v3.25 in swift
This is a bug and Facebook is currently "assigning this to the appropriate team".
To get updates to this issue follow this link:
https://developers.facebook.com/bugs/362995353893156/
and hit subscribe.
Some people have found success using the answers on this link (none have worked for me):
Facebook iOS8 SDK build module error for FBSDKCoreKit