Bring the total_forks under tasklist_lock.  When most of the fork code
icluding nr_threads is moved to copy_process() from do_fork() code in 2.6,
this is left out.

Althought accuracy of total_forks is not important, it would be nice to add
this.  It does not involve additional cost, and the code will be cleaner if
it is grouped with nr_threads.  The difference is, total_forks will
increase on fork, but nr_threads will increase on fork and decrease on the
exit.

I also moved extern decleration to sched.h from proc_misc.c.
Signed-off-by: Prasanna Meda <pmeda@akamai.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>