module-variable accesses pre-module-obarray if module is #f

module-variable accesses pre-module-obarray if module is #f

* libguile/modules.c (module-variable): If module is #f, access the
  pre-modules-array. This is so that nested-ref can work before the
  module system is booted, I think.

  Of course all of these dependency lines during bootstrap are just to
  make sure the system can be booted properly, either interpreted or
  compiled, so there's no one right way: there are many ways that could
  work.