RFC: configure option to disable daemon mode

[Rainer Orth]

Looking at rsync 2.5.5, I noticed that there is no way to disable the
daemon mode when building rsync.  I'd like to be able to do so since it
provides a trivial way for users to open up access to all files they can
read to anyone with access to the rsyncd port.  While it is true that users
can always build rsync themselves if they really want to do this (contrary
to our policy), I'd like to be able to provide an rsync installation which
doesn't support this capability out of the box.

While I can easily disable the handling of the daemon-mode related options
in options.c (usage) and be done with it, it might be useful to provide a
configure option to select this at build time and not include those parts
of the code that are only used in daemon mode.

A quick attempt to link rsync without the object files from DAEMON_OBJ
revealed that a couple of undefined symbols result from this, so one will
have to wrap a couple of code fragments in, say, HAVE_DAEMON to really
achieve this goal.

If there's any interest in such an option, I might work on a clean patch to
implement it.  Otherwise, I'll keep this simply as a local hack.

	Rainer

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Rainer Orth, Faculty of Technology, Bielefeld University