Log Message:
Changes 5.2.0:
* liblzma:
        - Added support for multi-threaded compression. See the
          lzma_mt structure, lzma_stream_encoder_mt(), and
          lzma_stream_encoder_mt_memusage() in <lzma/container.h>,
          lzma_get_progress() in <lzma/base.h>, and lzma_cputhreads()
          in <lzma/hardware.h> for details.
        - Made the uses of lzma_allocator const correct.
        - Added lzma_block_uncomp_encode() to create uncompressed
          .xz Blocks using LZMA2 uncompressed chunks.
        - Added support for LZMA_IGNORE_CHECK.
        - A few speed optimizations were made.
        - Added support for symbol versioning. It is enabled by default
          on GNU/Linux, other GNU-based systems, and FreeBSD.
        - liblzma (not the whole XZ Utils) should now be buildable
          with MSVC 2013 update 2 or later using windows/config.h.
* xz:
        - Fixed a race condition in the signal handling. It was
          possible that e.g. the first SIGINT didn't make xz exit
          if reading or writing blocked and one had bad luck. The fix
          is non-trivial, so as of writing it is unknown if it will be
          backported to the v5.0 branch.
        - Multi-threaded decompression can be enabled with the
          --threads (-T) option.
        - New command line options in xz: --single-stream,
          --block-size=SIZE, --block-list=SIZES,
          --flush-timeout=TIMEOUT, and --ignore-check.
        - xz -lvv now shows the minimum xz version that is required to
          decompress the file. Currently it is 5.0.0 for all supported
          .xz files except files with empty LZMA2 streams require 5.0.2.
* xzdiff and xzgrep now support .lzo files if lzop is installed.
  The .tzo suffix is also recognized as a shorthand for .tar.lzo.