Upgrade xz from 5.0.4 to 5.0.7 on the vendor branch

Upgrade xz from 5.0.4 to 5.0.7 on the vendor branch

5.0.7 (2014-09-20)
    * Fix regressions introduced in 5.0.6:
        - Fix building with non-GNU make.
        - Fix invalid Libs.private value in liblzma.pc which broke
          static linking against liblzma if the linker flags were
          taken from pkg-config.
5.0.6 (2014-09-14)
    * xzgrep now exits with status 0 if at least one file matched.
    * A few minor portability and build system fixes
5.0.5 (2013-06-30)
    * lzmadec and liblzma's lzma_alone_decoder(): Support decompressing
      .lzma files that have less common settings in the headers
      (dictionary size other than 2^n or 2^n + 2^(n-1), or uncompressed
      size greater than 256 GiB). The limitations existed to avoid false
      positives when detecting .lzma files. The lc + lp <= 4 limitation
      still remains since liblzma's LZMA decoder has that limitation.

      NOTE: xz's .lzma support or liblzma's lzma_auto_decoder() are NOT
      affected by this change. They still consider uncommon .lzma headers
      as not being in the .lzma format. Changing this would give way too
      many false positives.
    * xz:
        - Interaction of preset and custom filter chain options was
          made less illogical. This affects only certain less typical
          uses cases so few people are expected to notice this change.

          Now when a custom filter chain option (e.g. --lzma2) is
          specified, all preset options (-0 ... -9, -e) earlier are on
          the command line are completely forgotten. Similarly, when
          a preset option is specified, all custom filter chain options
          earlier on the command line are completely forgotten.

          Example 1: "xz -9 --lzma2=preset=5 -e" is equivalent to "xz -e"
          which is equivalent to "xz -6e". Earlier -e didn't put xz back
          into preset mode and thus the example command was equivalent
          to "xz --lzma2=preset=5".

          Example 2: "xz -9e --lzma2=preset=5 -7" is equivalent to
          "xz -7". Earlier a custom filter chain option didn't make
          xz forget the -e option so the example was equivalent to
          "xz -7e".
        - Fixes and improvements to error handling.
        - Various fixes to the man page.
    * xzless: Fixed to work with "less" versions 448 and later.
    * xzgrep: Made -h an alias for --no-filename.
    * Include the previously missing debug/translation.bash which can
      be useful for translators.
    * Include a build script for Mac OS X. This has been in the Git
      repository since 2010 but due to a mistake in Makefile.am the
      script hasn't been included in a release tarball before.