https://bugs.gentoo.org/883075

--- motif-2.3.8/clients/mwm/WmError.c
+++ motif-2.3.8/clients/mwm/WmError.c
@@ -131,7 +131,7 @@
     XSetIOErrorHandler (WmXIOErrorHandler);
 
     XtSetWarningHandler (WmXtWarningHandler);
-    XtSetErrorHandler (WmXtErrorHandler);
+    XtSetErrorHandler ((XtErrorHandler _X_NORETURN)WmXtErrorHandler);
 
 } /* END OF FUNCTION WmInitErrorHandler */