Unresolved inheritance operation

I was experimenting with getting DDD running on a Macintosh and came up
with this error:

Setting BOOTDISK flag to FFFFFFFF
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-darwin16.3.0) 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 manual.

We thank you for your support.

ddd: Cannot save options
[1]   Done                    ./run_canon_fw.sh EOSM2,firmware="boot=1" -s
-S

-------------------------------------
Here is a forum post that explains what we're doing--installed DDD through
Homebrew (see bottom of post):

http://www.magiclantern.fm/forum/index.php?topic=15895.msg186210#msg186210

and here is the contents of the log file:

GNU DDD 3.3.12 (i386-apple-darwin16.3.0)
Copyright (C) 1995-1999 Technische Universit?t Braunschweig, Germany.
Copyright (C) 1999-2001 Universit?t Passau, Germany.
Copyright (C) 2001 Universit?t des Saarlandes, Germany.
Copyright (C) 2001-2009 Free Software Foundation, Inc.

Compiled with GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)
Requires X11R6, Xt11R6, Motif 2.3.6 (Motif Version 2.3.6)
Includes XPM 3.4.11, Athena Panner (7000002L), Manual, App defaults, DDD
core
Built 2017-01-27 by (unknown).
$  ddd --debugger arm-none-eabi-gdb -x EOSM2/debugmsg.gdb
!  Xt error: Unresolved inheritance operation
!  Xt error
!  Cannot save options