12167 Update prototypes to 2020

*** 8,18 ****
   * source.  A copy of the CDDL is also available via the Internet at
   * http://www.illumos.org/license/CDDL.
   */
  
  /*
!  * Copyright 2019 <contributor>
   */
  
  #ifndef _PROTOTYPE_H
  #define _PROTOTYPE_H
  
--- 8,18 ----
   * source.  A copy of the CDDL is also available via the Internet at
   * http://www.illumos.org/license/CDDL.
   */
  
  /*
!  * Copyright 2020 <contributor>
   */
  
  #ifndef _PROTOTYPE_H
  #define _PROTOTYPE_H