Don't die on TYPE_CODE_UNDEF nodes as base classes.

(Previous checkin died due to cvs bug.)

gdb/buildsym.c

@@ -2690,9 +2690,14 @@ read_struct_type (pp, type, objfile)
   {
     int i;
     for (i = 0; i < TYPE_N_BASECLASSES (type); ++i)
+      {
+	if (TYPE_CODE (TYPE_BASECLASS (type, i)) == TYPE_CODE_UNDEF)
+	  /* @@ Memory leak on objfile->type_obstack?  */
+	  return error_type (pp);
 	TYPE_NFN_FIELDS_TOTAL (type) +=
 	  TYPE_NFN_FIELDS_TOTAL (TYPE_BASECLASS (type, i));
       }
+  }
 
   for (n = nfn_fields; mainlist; mainlist = mainlist->next) {
     --n;                      /* Circumvent Sun3 compiler bug */