5819 want dumpadm(1m) option to print estimated dump size

*** 18,27 ****
--- 18,28 ----
   *
   * CDDL HEADER END
   */
  /*
   * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
+  * Copyright 2015 Nexenta Systems, Inc. All rights reserved.
   */
  
  #ifndef _DCONF_H
  #define _DCONF_H
  
*** 69,78 ****
--- 70,80 ----
  extern int dconf_close(dumpconf_t *);
  extern int dconf_write(dumpconf_t *);
  extern int dconf_update(dumpconf_t *, int);
  extern void dconf_print(dumpconf_t *, FILE *);
  extern int dconf_write_uuid(dumpconf_t *);
+ extern int dconf_get_dumpsize(dumpconf_t *);
  
  extern int dconf_str2device(dumpconf_t *, char *);
  extern int dconf_str2savdir(dumpconf_t *, char *);
  extern int dconf_str2content(dumpconf_t *, char *);
  extern int dconf_str2enable(dumpconf_t *, char *);