10116 mech_dh needs smatch fixes

*** 24,34 ****
   *
   *      Copyright (c) 1997, by Sun Microsystems, Inc.
   *      All rights reserved.
   */
  
! #pragma ident   "%Z%%M% %I%     %E% SMI"
  
  #include <stdlib.h>
  #include <string.h>
  #include <syslog.h>
  #include <dh_gssapi.h>
--- 24,36 ----
   *
   *      Copyright (c) 1997, by Sun Microsystems, Inc.
   *      All rights reserved.
   */
  
! /*
!  * Copyright (c) 2018, Joyent, Inc.
!  */
  
  #include <stdlib.h>
  #include <string.h>
  #include <syslog.h>
  #include <dh_gssapi.h>
*** 102,112 ****
          static int init_nis_pubkey = 0;
          static int (*nis_call)();
          static const char NIS_SYMBOL[] = "__rpcsec_gss_is_server";
  
          if (!init_nis_pubkey) {
!                 mutex_lock(&init_nis_pubkey_lock);
                  if (!init_nis_pubkey) {
                          void *dlhandle = dlopen(0, RTLD_NOLOAD);
                          if (dlhandle == 0) {
                                  syslog(LOG_ERR, "dh: Could not dlopen "
                                      "in dh_getpublickey for %s. "
--- 104,114 ----
          static int init_nis_pubkey = 0;
          static int (*nis_call)();
          static const char NIS_SYMBOL[] = "__rpcsec_gss_is_server";
  
          if (!init_nis_pubkey) {
!                 (void) mutex_lock(&init_nis_pubkey_lock);
                  if (!init_nis_pubkey) {
                          void *dlhandle = dlopen(0, RTLD_NOLOAD);
                          if (dlhandle == 0) {
                                  syslog(LOG_ERR, "dh: Could not dlopen "
                                      "in dh_getpublickey for %s. "
*** 115,125 ****
                                  nis_call = (int (*)())
                                          dlsym(dlhandle, NIS_SYMBOL);
                          }
                          init_nis_pubkey = 1;
                  }
!                 mutex_unlock(&init_nis_pubkey_lock);
          }
          if (nis_call && (*nis_call)()) {
                  int key_cached;
                  return (__getpublickey_cached_g(remote, keylen, algtype,
                                              pk, pklen, &key_cached));
--- 117,127 ----
                                  nis_call = (int (*)())
                                          dlsym(dlhandle, NIS_SYMBOL);
                          }
                          init_nis_pubkey = 1;
                  }
!                 (void) mutex_unlock(&init_nis_pubkey_lock);
          }
          if (nis_call && (*nis_call)()) {
                  int key_cached;
                  return (__getpublickey_cached_g(remote, keylen, algtype,
                                              pk, pklen, &key_cached));