RFC: liblzma and xz to FreeBSD base

[Martin Matuska]

Dear fellow devleopers,

I would like to propose an import of liblzma and the utilities xz, xzdec
and lzmainfo to base (vendor -> contrib).
As I was informed, libarchive is already lzma-ready, some of our
existing code could take advantage of liblzma instantly.

The source code is imported from:
http://tukaani.org/xz/xz-4.999.9beta.tar.gz

All GPLv2, LGPLv2.1 and GPLv3 parts are stripped from the code (they
cover only the build system and unimportant scripts).
liblzma, xz, xzdec, lzmainfo are public domain licensed.

A working patchset against HEAD (includes modified lesspipe.sh):
http://people.freebsd.org/~mm/patches/xz/

The only patched file is src/common/bswap.h, with the patch from the
archivers/xz port.

Comments and suggestions are welcome.

Thanks,
mm