DDD 3.3.12 (i386-apple-darwin20.1.0) gets Xt error

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Greetings!

I'm brushing off my assembly language skills by building a Forth 
interpreter from scratch on my Mac (V. 11.6).  The commands to build the 
executable are:

nasm -g -f macho64 -o forth.o forth.asm
ld -macosx_version_min 11.0.0 
-L/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/lib -lSystem 
-o forth forth.o

After a few days with lldb (which runs very nicely on that executable) I 
decided to give ddd a try.  I ran "brew install ddd" and that ran 
cleanly. Then when I tried to debug my NASM assembly language program 
with "ddd forth" (and also just "ddd"), I got this:

======
$ddd forth
Warning: locale not supported by Xlib, locale set to C
Warning: X locale modifiers not supported, using default
Creating "/Users/principal/.ddd/"...
Creating "/Users/principal/.ddd/"...done.
Creating "/Users/principal/.ddd/sessions/"...
Creating "/Users/principal/.ddd/sessions/"...done.
Creating "/Users/principal/.ddd/themes/"...
Creating "/Users/principal/.ddd/themes/"...done.
Error: Unresolved inheritance operation

Xt error (Unresolved inheritance operation).

Oops!  You have found a bug in DDD.

If you can reproduce this bug, please send a bug report
to <[email protected]>, giving a subject like

     DDD 3.3.12 (i386-apple-darwin20.1.0) gets Xt error

To enable us to fix the bug, you should include the following information:
* What you were doing to get this message.  Report all the facts.
* The contents of the `~/.ddd/log' file as generated by this session.
Please read also the section "Reporting Bugs" in the DDD manua
We thank you for your support.

ddd: Cannot save options
========

The log file contents follow:

GNU DDD 3.3.12 (i386-apple-darwin20.1.0)
Copyright (C) 1995-1999 Technische Universität Braunschweig, Germany.
Copyright (C) 1999-2001 Universität Passau, Germany.
Copyright (C) 2001 Universität des Saarlandes, Germany.
Copyright (C) 2001-2009 Free Software Foundation, Inc.

Compiled with GCC Apple LLVM 12.0.0 (clang-1200.0.32.27)
Requires X11R6, Xt11R7, Motif 2.3.8 (Motif Version 2.3.8)
Includes XPM 3.4.11, Athena Panner (7000002L), Manual, App defaults, DDD 
core
Built 2020-11-17 by (unknown).
$  ddd forth
!  Xt error: Unresolved inheritance operation
!  Xt error
!  Cannot save options

"ddd --manual" actually worked but I couldn't figure out how to navigate 
it (I haven't used GNU's info format in a couple of decades--sorry).

-- 

Daryl Lee
www.daryllee.com
Only those who risk going too far can possibly find out how far one can go.
   -- T.S. Eliot.


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