title: Xcode 8 does full project rebuild
body: <p>Having updated Swift + ObjC project to Xcode 8 (Swift 2.3) I found 50% or more of the time Xcode does a full rebuild of the project instead of an incremental build.</p>
  
  <p>The changes made are adding simple print statements. There seems to be no logic as to when it performs a full rebuild.</p>
  
  <p>It appears in the "Check dependencies" phase it decides this. On Xcode 7 this did not seem to be a problem.</p>
  
  <p>Has anyone else encountered this?</p>