New formula for CLN

The Class Library for Numbers (CLN) is a C++ library that provides an
efficient implementation of arbitrary precision arithmetic.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/cln.rb

@@ -0,0 +1,16 @@
+require 'formula'
+
+class Cln <Formula
+  url 'http://www.ginac.de/CLN/cln-1.3.1.tar.bz2'
+  homepage 'http://www.ginac.de/CLN/'
+  md5 'ede584cb1cafa66d56f42a3cf420469d'
+
+  depends_on "gmp"
+
+  def install
+    system "./configure", "--prefix=#{prefix}",
+                          "--disable-dependency-tracking",
+                          "--with-gmp=#{HOMEBREW_PREFIX}"
+    system "make install"
+  end
+end