Applied patch from Darryl Miles that prevents a segfault on an

error in "extresist".  The underlying error still exists and
causes a "Bad Device" error but no longer crashes magic.  See
github Issue #353.

Author: RTimothyEdwards

resis/ResJunct.c

@@ -55,6 +55,13 @@ ResNewSDDevice(tile, tp, xj, yj, direction, PendingList)
     tileJunk	*j;
 
     newnode = FALSE;
+
+    /* Watch for invalid client data.  If found, a "Bad Device" error will
+     * be generated which means "more debugging needed";  however, it will
+     * not cause a segmentation violation.
+     */
+    if (tp->ti_client == CLIENTDEFAULT) return;
+
     j = (tileJunk *) tp->ti_client;
     resDev = j->deviceList;
     if ((j->sourceEdge & direction) != 0)

resis/ResMain.c

@@ -1725,7 +1725,12 @@ ResGetDevice(pt, type)
             return (((tileJunk *)tile->ti_client)->deviceList);
     }
     else if (TTMaskHasType(&ExtCurStyle->exts_deviceMask, TiGetType(tile)))
-        return (((tileJunk *)tile->ti_client)->deviceList);
-
+    {
+	/* Failure to have a valid client data will result in a "Bad Device"
+	 * error and indicates a problem that needs debugging.
+	 */
+	if (tile->ti_client != CLIENTDEFAULT)
+            return (((tileJunk *)tile->ti_client)->deviceList);
+    }
     return NULL;
 }