Only compile once the module_under_autoload extension
Only compile once the module_under_autoload extension

* Compiling it twice and loading it twice actually causes a SEGV on MRI.

sgarciac/spec,nobu/rubyspec,sgarciac/spec,eregon/rubyspec,ruby/spec,eregon/rubyspec,sgarciac/spec,ruby/rubyspec,nobu/rubyspec,ruby/spec,ruby/spec,ruby/rubyspec,eregon/rubyspec,nobu/rubyspec