New formula botan

Botan is a BSD-licensed crypto library written in C++. It provides
applications with the ability to use a number of cryptographic
algorithms, as well as X.509 certificates and CRLs, PKCS Homebrew/homebrew#10
certificate requests, a filter/pipe message processing system, and
a wide variety of other features, all written in portable C++.

Formula/botan.rb

@@ -0,0 +1,16 @@
+require 'formula'
+
+class Botan <Formula
+  url 'http://botan.randombit.net/files/Botan-1.8.8.tbz'
+  homepage 'http://botan.randombit.net/'
+  md5 'cb7cf79c34414cdf1f7a25569d7b82ac'
+
+  def install
+    inreplace 'src/build-data/makefile/unix_shr.in' do |s|
+      s.change_make_var! 'SONAME', "#{lib}" + '/$(LIBNAME)-$(SO_VERSION).%{so_suffix}'
+    end
+
+    system "./configure.py", "--prefix=#{prefix}"
+    system "make install"
+  end
+end