I just attached a battery to my breadboard Game Frame and my code worked exactly as intended. Can you describe what you mean when you say it didn’t work?
With my code, you do have to set the time once, but after that it retains the time between power cycles. Your code change to adjustClock() will set the time to compile time rather than ask the user to manually set it. At best, this will be a second or two behind (since it’s not actually set until after compile, when the board reboots and runs code), and it will revert to compile time if the battery dies or is removed (rather than ask the user to reset the clock).