geuler:rbx-cpp brian$ git diff
diff --git a/spec/compiler/spec_helper.rb b/spec/compiler/spec_helper.rb
index 38e2e82..a8f97d0 100644
--- a/spec/compiler/spec_helper.rb
+++ b/spec/compiler/spec_helper.rb
@@ -1,5 +1,6 @@
 require File.dirname(__FILE__) + '/../spec_helper'

+unless defined?(RUBY_ENGINE) and RUBY_ENGINE == 'rbx'
 $: << 'lib'

 require File.dirname(__FILE__) + '/../../lib/compiler/compiler'
@@ -20,6 +21,8 @@ require "sexp_processor"
 load "kernel/delta/string.rb"

 require 'ruby_parser' # for s(...)
+end
+
 def parse ruby
   ruby.to_sexp("spec")
 end