Some parameters and -v option can be restricted to be applied conditionally,
by prefixing "(condition)" to a parameter.
Currently, condition is a list of client host which is described
in HostList.
For example, "(.localnet)-vs" specifies to suppress logging when the client
is from local networks.
Parameters which can be conditional with this prefix are:
BASEURL, DELAY, DELEGATE,
FCL, FSV, FFROMCL, FFROMSV, FTOCL, FTOSV,
LOGFILE, MAXIMA, RIDENT and TIMEOUT.
This mechanism does not work for UDP sockets.