diff -ruN ddd-3.3.12/ddd/exit.C ddd-my/ddd/exit.C
--- ddd-3.3.12/ddd/exit.C	2009-02-11 18:25:07.000000000 +0100
+++ ddd-my/ddd/exit.C	2020-09-27 03:23:14.713650981 +0200
@@ -769,7 +769,11 @@
 
 static XtAppContext xt_error_app_context = 0;
 
+#ifdef __clang__
+static void ddd_xt_error(String message = 0) _X_NORETURN
+#else
 static void ddd_xt_error(String message = 0)
+#endif
 {
     ddd_has_crashed = true;