9971 Make getrandom(2) a public interface

*** 8,18 ****
   * source.  A copy of the CDDL is also available via the Internet at
   * http://www.illumos.org/license/CDDL.
   */
  
  /*
!  * Copyright (c) 2015, Joyent, Inc.
   */
  
  /*
   * getrandom system call implementation
   */
--- 8,18 ----
   * source.  A copy of the CDDL is also available via the Internet at
   * http://www.illumos.org/license/CDDL.
   */
  
  /*
!  * Copyright (c) 2018, Joyent, Inc.
   */
  
  /*
   * getrandom system call implementation
   */
*** 34,45 ****
   * than INT_MAX.
   */
  #define MAXRANDBYTES    1024
  #define MAXURANDBYTES   INT_MAX
  
! int
! getrandom(void *bufp, size_t buflen, int flags)
  {
          int out = 0;
          uint8_t rbytes[128];
          uint8_t *buf = bufp;
  
--- 34,45 ----
   * than INT_MAX.
   */
  #define MAXRANDBYTES    1024
  #define MAXURANDBYTES   INT_MAX
  
! ssize_t
! getrandom(void *bufp, size_t buflen, unsigned int flags)
  {
          int out = 0;
          uint8_t rbytes[128];
          uint8_t *buf = bufp;