re #13613 rb4516 Tunables needs volatile keyword

*** 20,29 ****
--- 20,32 ----
   */
  /*
   * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
+ /*
+  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
+  */
  
  /*
   * Copyright (c) 2013, Joyent, Inc. All rights reserved.
   */
  
*** 198,208 ****
  /* lwp states */
  #define LWP_USER        0x01            /* Running in user mode */
  #define LWP_SYS         0x02            /* Running in kernel mode */
  
  #if     defined(_KERNEL)
! extern  int     lwp_default_stksize;
  extern  int     lwp_reapcnt;
  
  extern  struct _kthread *lwp_deathrow;
  extern  kmutex_t        reaplock;
  extern  struct kmem_cache *lwp_cache;
--- 201,211 ----
  /* lwp states */
  #define LWP_USER        0x01            /* Running in user mode */
  #define LWP_SYS         0x02            /* Running in kernel mode */
  
  #if     defined(_KERNEL)
! extern  volatile int    lwp_default_stksize;
  extern  int     lwp_reapcnt;
  
  extern  struct _kthread *lwp_deathrow;
  extern  kmutex_t        reaplock;
  extern  struct kmem_cache *lwp_cache;