* win32/win32.c (opendir_internal, rb_w32_opendir): extract and merge
  common part of rb_w32_opendir() and rb_w32_uopendir().

* dir.c (do_opendir, glob_helper): encoding.

* dir.c (dir_initialize, do_opendir): convert path to UTF-8 and call
  rb_w32_uopendir() instead of rb_w32_opendir() on Windows.
  fixes #4491, reported by Joey Zhou.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31372 b2dd03c8-39d4-4d8f-98ff-823fe69b080e