So you are humming along and everything is going great. Then all of a sudden you start getting the error message “Warning: –resource-rules has been deprecated in Mac OS X >= 10.10”, especially if you are using some kind of tool to re-sign code.
Apparently, in your build settings for your target in Xcode, there is a Code Signing Resource Rules Path entry that is no longer supported. Once this is removed and the app is rebuilt, the message should no longer appear. Of course, if you are re-signing an app that you do not have the source code for, this could be a challenge.
Here is the technical note from Apple that describes the issue:
BTW, Happy 60th Birthday to the best rock guitar player of all time, Joe Satriani. I am looking forward to seeing Joe in a few weeks at the G4 Experience on Long Island.