gnu: Add plzip.

* gnu/packages/compression.scm (plzip): New public variable.

gnu/packages/compression.scm

@@ -2023,3 +2023,33 @@ all functions are thread-safe.  The library should never crash, even in case of
 corrupted input.")
     (license (list license:bsd-2        ; the library itself
                    license:gpl2+))))    ; main.c (i.e. minilzip used by tests)
+
+(define-public plzip
+  (package
+    (name "plzip")
+    (version "1.6")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append "http://download.savannah.gnu.org/releases/lzip/"
+                           name "/" name "-" version ".tar.gz"))
+       (sha256
+        (base32 "0z2cs6vn4xl65wakd013xl3sdfpg8dr0cvcjwc2slh8y9bz7j7ax"))))
+    (build-system gnu-build-system)
+    (inputs
+     `(("lzlib" ,lzlib)))
+    (home-page "http://www.nongnu.org/lzip/plzip.html")
+    (synopsis "Parallel lossless data compressor for the lzip format")
+    (description
+     "Plzip is a massively parallel (multi-threaded) lossless data compressor
+and decompressor that uses the lzip file format (.lz).  Files produced by plzip
+are fully compatible with lzip and can be rescued with lziprecover.
+On multiprocessor machines, plzip can compress and decompress large files much
+faster than lzip, at the cost of a slightly reduced compression ratio (0.4% to
+2%).  The number of usable threads is limited by file size: on files of only a
+few MiB, plzip is no faster than lzip.
+Files that were compressed with regular lzip will also not be decompressed
+faster by plzip, unless the @code{-b} option was used: lzip usually produces
+single-member files which can't be decompressed in parallel.")
+    (license (list license:bsd-2        ; arg_parser.{cc,h}
+                   license:gpl2+))))    ; everything else