dir.c: make ASCII-8BIT
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52031 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
dir.c: make ASCII-8BIT
US-ASCII, like as Dir.glob.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52031 b2dd03c8-39d4-4d8f-98ff-823fe69b080e