Add jansson package

packages/jansson.rb

+require 'package'
+
+class Jansson < Package
+  description 'Jansson is a C library for encoding, decoding and manipulating JSON data.'
+  homepage 'http://www.digip.org/jansson/'
+  version '2.10'
+  source_url 'https://github.com/akheron/jansson/archive/v2.10.tar.gz'
+  source_sha256 'b0a899f90ade82e42da0ecabc8af1fa296d69691e7c0786c4994fb79d4833ebb'
+
+  binary_url ({
+  })
+  binary_sha256 ({
+  })
+
+  depends_on 'cmake' => :build
+
+  def self.build
+    system "cmake . -DPREFIX=#{CREW_PREFIX} -DCMAKE_INSTALL_LIBDIR=#{CREW_DEST_LIB_PREFIX}"
+  end
+
+  def self.install
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install"
+  end
+end