I hadn't noticed that the RTC battery failed on one of my computers and it didn't have NTP. While doing an update it got stuck building sys-apps/file where configure completed successfully and then make called configure again in a loop. I reproduced it on another system with this: date -s 01/01/2018 emerge sys-apps/file --oneshot
This will happen with many things if your clock is broken. I don't think we can really do anything about this.
(In reply to Sam James from comment #1) > This will happen with many things if your clock is broken. I don't think we > can really do anything about this. Fair enough but I think configure can check for sane clock, at least htop does and fails gracefully
It'd be hard to get such a check in every packages' autotools setup, but we could maybe have Portage do a quick sanity check?