Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

The r184588 changed the layout of struct export_args, causing an ABI
breakage for old mount(2) syscall, since most struct <filesystem>_args
embed export_args. The mount(2) is supposed to provide ABI
compatibility for pre-nmount mount(8) binaries, so restore ABI to
pre-r184588.

Requested and reviewed by: bde
MFC after: 2 weeks

Forced commit and #include changes for repo copy from
sys/isofs/cd9660 to sys/fs/cd9660.

Discussed on freebsd-current.

/* -> /*- for copyright notices, minor format tweaks as necessary

Remove advertising clause from University of California Regent's
license, per letter dated July 22, 1999 and email from Peter Wemm,
Alan Cox and Robert Watson.

Approved by: core, peter, alc, rwatson

- Support for multibyte charsets in LIBICONV.
- CD9660_ICONV, NTFS_ICONV and MSDOSFS_ICONV kernel options
(with corresponding modules).
- kiconv(3) for loadable charset conversion tables support.

Submitted by: Ryuichiro Imura <imura@ryu16.org>

Add a mount time option which slightly relaxes checks for valid Joilet
extensions.

PR: kern/23315
Reviewed by: adrian

Add $FreeBSD$

Add support for Joliet extensions to the iso9660 fs. The related PR
cannot yet be closed, though.

I hope I got all credits right, and that the multiple submitted by lines
do not break anyone's scripts...

PR: kern/5038, kern/5567
Submitted by: Keith Jang <keith@email.gcn.net.tw>
Submitted by: Joachim Kuebart <joki@kuebart.stuttgart.netsurf.de>
Submitted by: Byung Yang <byung@wam.umd.edu>
Submitted by: Motomichi Matsuzaki <mzaki@e-mail.ne.jp>

Add support for ISO9660 multi-session CD-ROMs. This is just nothing
but searching the directory on something else than the default
location.

NB: this comprises an interface change to the mount_cd9660(8)
utility (commit will follow). You need to rebuild both.

I've got similar patches for RELENG_2_2, should i commit them too?

Import 4.4BSD-Lite2 onto the vendor branch, note that in the kernel, all
files are off the vendor branch, so this should not change anything.

A "U" marker generally means that the file was not changed in between
the 4.4Lite and Lite-2 releases, and does not need a merge. "C" generally
means that there was a change.
[note, new file: cd9660_mount.h]