I've got a physical bit of tin that I'm playing around with. It has a livecd booted. I ssh into it, enter chroot, happy days.
I've been trying to install tmux, but libevent just wouldn't finish configuring. I had forgetten about it and left over the weeked. Found it still running (probably in loops) this morning. Quick websearch did not yield anything obvious, thought I'd sync the repo in hopes it was an ebuild issue. That threw up on me with SSL errors, complaining the certs are not valid, yet. This was the hint I needed. After setting the correct time the build went through in seconds.
I don't understand why it got in the way in the first place, but I guess it's not something people would run into all that often. Something to keep in mind, though!
For even more amusement, try correcting the system clock after fetching the source but before compiling certain packages, and watch ninja flail around because it can't deal with source from the future, until it finishes its thousand default iterations and causes portage to error out. (My system is only about twelve hours in the future on startup, fortunately, so it's self-correcting if you wait overnight. It took me a while to figure out what the actual problem was.)
Timestamp of the source actually makes sense! Thanks for that! :D