* gc.c, gc.h (rb_objspace_each_objects_without_setup):
  Add a new (hidden) C-API to iterate objspace snapshot.
  This API is not safe to call any C-APIs in a given callback
  function. Be careful to use this C-API.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45505 b2dd03c8-39d4-4d8f-98ff-823fe69b080e