Log Message:
Import libarchive-3.1.2 as wip/libarchive.

The libarchive library features:

* Support for a variety of archive and compression formats ?.
* Robust automatic format detection ?, including archive/compression
  combinations such as tar.gz.
* Zero-copy internal architecture ? for high performance.
* Streaming architecture eliminates all limits on size of archive, limits on
  entry sizes depend on particular formats.
* Carefully factored code to minimize bloat when programs are statically linked.
* Growing test suite ? to verify correctness of new ports.
* Works on most POSIX-like systems (including FreeBSD, Linux, Solaris, etc.)
* Supports Windows, including Cygwin, MinGW, and Visual Studio.

The bsdtar and bscpio command-line utilities are feature- and performance-
competitive with other tar and cpio implementations: