adding a catch to a possible ruby bug

Rakefile

@@ -278,3 +278,16 @@ end
 
 
 ################################
+
+if defined?(RUBY_ENGINE) && RUBY_ENGINE == "ruby"
+  module Kernel
+    alias :_at_exit :at_exit
+    def at_exit(&block)
+      _at_exit do
+      exit_status = $!.status if $!.is_a?(SystemExit)
+      block.call
+      exit exit_status if exit_status
+    end
+    end
+  end
+end