I was a few minutes away from leaving, when our build team leader informed me that he'd been asked to do a build that didn't follow our build processes (or any sane process for producing code that goes to a customer). After discussing how to do this, we got approval from our boss and are going forward with the work.
I've got the first step (copying the code from one area under Perforce to a new area under Perforce), which hopefully won't take forever. So I should still be able to make my evening plans (karate class at 6:40).
I'd be more annoyed at this, except the engineer who actually has to submit the fix is in Madrid, where it is already almost Midnight.