OpenMotif is broken.  libXt.6.dylib was provided as a workaround to try and not break existing applications that rely on OpenMotif's broken behavior.  I suggest you try and fix OpenMotif

Is this a joke or the normal developer response on Bugzilla. Since OpenMotif worked with XQuartz ever since apple introduce MacOS X, if it stopped working from version 2.7.8 to 2.7.9, in my view it is a problem with XQuartz and the X11 and Xt libraries provided by XQuartz.

Just for the record, almost two years ago, I opened a bug report on Bugzilla about LibreOffice loosing figures and equation in a fairly complex documents (with lots of figures and equations), which was closed in a similar ignorant fashion in a short time. Since, could not tolerate a software that cannot save documents a moved away from LibreOffice and stopped advocating. About six month ago, I started to get e-mails regarding my bug report as it was reopened, because some developer realized that a serious bug was introduced exactly at the version I pointed out when they moved to some sort of parallel execution of writing out the ODF document. I hope, we won't have something similar here.

Since, I have no means to fix OpenMotif, I will go ahead and report this bug on OpenMotif's bug reporting system and I will refer to this bug report, however, I would have thought that the XQuartz developer team was in permanent contact with OpenMotif developers, since OpenMotif is not some sort of home grown esoteric software, but the granddaddy of user interfaces on the UNIX/Linux platform that was around for minimum three decades (and is still maintained by the Open Group, http://www.opengroup.org/openmotif).

Best regards,

Balazs

I reported the problem to Motif developers about 5-10 years ago, and I never heard any response.  OpenMotif is not really in active development, so that's not surprising. 

I fixed the related bug in libXaw and libXaw3d, and I went to great lengths to maintain binary compatibility with the broken implementations which relied on libXt being built with -Wl,-flat_namespace.  The fact that you experience failure when recompiling against the non flat-namespace libXt is simply evidence of the bug being with OpenMotif.  There's nothing more I can do.  I've pointed many people in the right direction to fixing the bug, and you can see my comments in https://echelog.com/logs/browse/macports/1452121200 including a reference to a starting point on a patch for the fix.