Merge pull request #298 from cstrouse/add-chicken

Add package for chicken scheme compiler

packages/chicken.rb

+require 'package'
+
+class Chicken < Package
+  version '4.11.0'
+  source_url 'https://code.call-cc.org/releases/4.11.0/chicken-4.11.0.tar.gz'
+  source_sha1 'b8b1e8b741a5ea5b318c449c3bf8a42f8de8ba69'
+
+  def self.build
+    system "make", "PLATFORM=linux"
+  end
+
+  def self.install
+    system "make", "DESTDIR=#{CREW_DEST_DIR}", "install", "PLATFORM=linux"
+  end
+end