[PATCH] init_thread_union really needed by modules?

init_thread_union doesn't need to be exported to modules.

We haven't exported the symbol on ia64 for ages, and we should be able
to make the init_thread_union local to arch/ARCH/kernel/init_task.c and
that in turn would let us remove its declaration from
include/linux/sched.h altogether (i.e., no more ugly #ifdefs).

kernel/ksyms.c

@@ -592,7 +592,6 @@ EXPORT_SYMBOL(__tasklet_hi_schedule);
 /* init task, for moving kthread roots - ought to export a function ?? */
 
 EXPORT_SYMBOL(init_task);
-EXPORT_SYMBOL(init_thread_union);
 
 EXPORT_SYMBOL(tasklist_lock);
 EXPORT_SYMBOL(find_task_by_pid);