kernel - Fix deadlock in tmpfs

* If the pageout daemon is paging out a file on a tmpfs mount concurrent
  with an unmount of same, a deadlock can occur.

* Fix the node vs vnode lock order in the tmpfs umount code.
kernel - Fix cross-mount handling in tmpfs hardlink code

* Fix tmpfs to properly report EXDEV when a cross-mount hardlink is
  attempted instead of asserting and causing a panic.

Reported-by: ftigeot
iso639: Add Standard Moroccan Tamazight.

See http://www.loc.gov/standards/iso639-2/php/code_changes.php
hier.7: Document that /boot/kernel is a directory and has the modules too.

While here, also remove /usr/include/objc.
libdmsg: Fix pointer dereference.
Use NULL for pointers in a couple of places.