Import of code from heimdal

This commit updates the code imported from heimdal to
4a438db29d361b7e5f47b86ced1482a96cde86ea (switch-from-svn-to-git-3008-g4a438db)

Upstream changes are:

Michael Meffie (1):
      drop __restrict some more, to please old compilers

Reviewed-on: http://gerrit.openafs.org/8003
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit 99238baed75205fd7a1885ed6b8fc8505d4faf95)

Change-Id: I27def01d28c0d4265d1675257625f0d0f3c614d2
Reviewed-on: http://gerrit.openafs.org/9932
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
out-of-tree-build: extend configuration,

namely libafsdep-files and configure-libafs.ac
so that building the kernel-module on linux in a separate
obj-directory works.

Reviewed-on: http://gerrit.openafs.org/8012
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit c2b13458498e8c27aa6eb1f2a777cf9bfe4488df)

Change-Id: I85d3f9b998f45966af1fef65bd4748ad0c38ee99
Reviewed-on: http://gerrit.openafs.org/9933
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>