STANDARD EZMLM DATABASE INTERFACE

The sub-std.c file comprises the ezmlm subscriber database interface. issub and
subscribe are backwards compatible with ezmlm-0.53 in terms of function,
but use a case-insensitive hash for address storage, and take a few
extra args to be plug-in compatible with alternative interfaces. Logging to
the subscriber log (DIR/Log) is done from subscribe rather than externally,
and the subscriber from line is logged as well.

searchlog allows access to DIR/Log.

putsubs does all output of subscriber addresses, both to qmail for subscibers,
moderator sendouts, etc, and to list subscribers in reply to the -list command.

Alternative subscriber db interface routines should perform equivalent services,
and fall back to these services if the alternative interface is not configured,
e.g. if DIR/subdb doe not exist.