use rb_locale_str_new
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56330 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
use rb_locale_str_new
rb_locale_str_new with the length. [Feature #12659]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56330 b2dd03c8-39d4-4d8f-98ff-823fe69b080e