I forgot to enable devfs in the kernel I compiled yesterday. The system booted fine but told me that it would be much happier with devfs compiled in.
I’ll make it happy this afternoon.
Update: Kernel is recompiled, I rebooted the box and it came back up SSHable.
Mental note: when running a Gentoo machine that will never run X, change your USE statement to USE="-X" which will make sure that stuff like Xfree86 isn’t installed when you try to install PHP. Oops.