New formula: libtar

libtar provides a C interface to tar files. It installs include and
library files as well as an executable called libtar, which provides
similar functionality to tar and gnu-tar. I think there should be
no conflicts since the executable has a different name.

Closes #18780.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Library/Formula/libtar.rb

@@ -0,0 +1,15 @@
+require 'formula'
+
+class Libtar < Formula
+  homepage 'http://www.feep.net/libtar/'
+  url 'ftp://ftp.feep.net/pub/software/libtar/libtar-1.2.11.tar.gz'
+  sha1 '9611f23024b0e89aad1cfea301122186b3c160f8'
+
+  def install
+    system "./configure", "--disable-debug",
+                          "--disable-dependency-tracking",
+                          "--prefix=#{prefix}",
+                          "--mandir=#{man}"
+    system "make install"
+  end
+end