[PATCH] add EXPORT_SYMBOL_GPL_FUTURE() to RCU subsystem

As the RCU symbols are going to be changed to GPL in the near future,
lets warn users that this is going to happen.

Cc: Paul McKenney <paulmck@us.ibm.com>
Acked-by: NDipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

kernel/rcupdate.c

@@ -609,7 +609,7 @@ module_param(qlowmark, int, 0);
 module_param(rsinterval, int, 0);
 #endif
 EXPORT_SYMBOL_GPL(rcu_batches_completed);
-EXPORT_SYMBOL(call_rcu);  /* WARNING: GPL-only in April 2006. */
-EXPORT_SYMBOL(call_rcu_bh);  /* WARNING: GPL-only in April 2006. */
+EXPORT_SYMBOL_GPL_FUTURE(call_rcu);	/* WARNING: GPL-only in April 2006. */
+EXPORT_SYMBOL_GPL_FUTURE(call_rcu_bh);	/* WARNING: GPL-only in April 2006. */
 EXPORT_SYMBOL_GPL(synchronize_rcu);
-EXPORT_SYMBOL(synchronize_kernel);  /* WARNING: GPL-only in April 2006. */
+EXPORT_SYMBOL_GPL_FUTURE(synchronize_kernel); /* WARNING: GPL-only in April 2006. */