s_assert requires some higher-level functionality that shouldn't be
present in ircd_defs.h. ircd_defs.h is used by ssld, which has no notion
of logging or sending IRC messages. Additionally, some of the headers
s_assert depends on result in conflicting definitions in ssld.c.
This change also fixes the compile when using --enable-assert=soft.
This changes flattened /links output to disclose less
routing information and slightly increases memory "leak"
from server names that do not come back anymore.