libc.so.7: undefined reference to `rpc_call'

Apologies in advance, as this is on RELENG_11. But I'm not on the releng list.
I get
libc.so.7: undefined reference to `rpc_call'
building world on a jail I created to update some older boxes that are well
past due. The jail(8) host is running a recent -CURRENT, and the jail is
running 11.1 from the most recent install media for releng.

Is this a known problem? If at all possible I'd like to stay as close
to the version of 11 I'm currently attempting to build. Anyway, any information
is greatly appreciated.

Thanks!

--Chris