This patch adds the option -master to the VNC server.

With this option enabled the first connection to the server requires
authentication while subsequent connections don't require any
authentication but are presented in view-only mode. This is useful
when using VNC for didactics because you don't want your students to
know you VNC password and don't want them to modify your desktop.

This patch is written against the source of the package vnc-3.3.7 of
the Gentoo Distribution.

manu-patch	10.10.2003	paolini@math.unifi.it