Attempting to create a local binary build of the Engine that includes iOS currently fails. The error message that appears ("ERROR: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.") is not very clear about what needs to be fixed.
[/Script/IOSRuntimeSettings.IOSRuntimeSettings] RemoteServerName= RSyncUsername=
RESULT:
The build fails during the Compile UnrealHeaderTool Mac step, and shows the error ERROR: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
EXPECTED:
The build completes successfully, or a more descriptive error is provided.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-60078 in the post.