Hand-holding please - openmotif

[Dave Horsfall]

:error:archivefetch org.macports.archivefetch for port openmotif returned: 
xorg-libXt must be installed with +flat_namespace.

How exactly do I do this?  I have never ever touched anything to do with 
Macports, other than as a dumb user...  Oops: one change (just the one,
under advice) was "revupgrade_mode report" uncommented.

With the Mac, I am but a lowly end-user, trying to learn more...

-- 
Dave Horsfall DTM (VK2KFU)  "Those who don't understand security will suffer."