S2PLOT is not open source at this stage.  This is unlikely to change
in the next six months.
This is the first request we have had for a *BSD build of S2PLOT.  If
you can manage by using "Linux emulation" then I recommend that for
the time being.
Thanks,
David.
with no other requests for a *BSD build of S2PLOT, our intention for
the
time being is to develop new features rather than support this
operating
system.
David Barnes.