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.
Altering localClient->F without updating the FD hash leaves the struct
Client in the FD hash indefinitely which causes a crash later if the
struct is reused for a remote client. It also prevents error messages
from ssld showing up on IRC properly.
