11584 ::xcall would be useful
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>

*** 22,32 ****
   * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  /*
   * Copyright (c) 2013, 2015 by Delphix. All rights reserved.
!  * Copyright (c) 2015, Joyent, Inc.
   */
  
  #ifndef _MDB_CTF_H
  #define _MDB_CTF_H
  
--- 22,32 ----
   * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  /*
   * Copyright (c) 2013, 2015 by Delphix. All rights reserved.
!  * Copyright 2018 Joyent, Inc.
   */
  
  #ifndef _MDB_CTF_H
  #define _MDB_CTF_H
  
*** 140,149 ****
--- 140,150 ----
  
  extern ssize_t mdb_ctf_offset_to_name(mdb_ctf_id_t, ulong_t, char *, size_t,
      int, mdb_ctf_id_t *, ulong_t *);
  
  #define MDB_CTF_VREAD_QUIET             0x100
+ #define MDB_CTF_VREAD_IGNORE_ABSENT     0x200
  
  extern int mdb_ctf_vread(void *, const char *, const char *,
      uintptr_t, uint_t);
  extern int mdb_ctf_readsym(void *, const char *, const char *, uint_t);