it's used to register a callback for a tap listener invoked if the
specified command line argument is specified to the "-z" flag.
Move it, along with routines to:
look up a "-z" argument in the table constructed by
"register_tap_listener_cmd_arg()" and either save the full
argument to "-z" and the corresponding listener if it's found or
return a failure indication if it isn't;
list the available tap listeners;
call the "init" routines for the tap listeners saved in the
table above;
and have Ethereal and Tethereal use those routines.
svn path=/trunk/; revision=13993
Lars Roland