From: Rusty Russell <rusty@rustcorp.com.au>

1) Create an in_sched_functions() function in sched.c and make the
   archs use it.  (Two archs have wchan #if 0'd out: left them alone).

2) Move __sched from linux/init.h to linux/sched.h and add comment.

3) Rename __scheduling_functions_start_here/end_here to __sched_text_start/end.

Thanks to wli and Sam Ravnborg for clue donation.