It supports to enable frozen string literal and add `--norc` option for
disable to `.gemrc` configuration.
See 2.5.2 release notes for other fixes and enhancements.
a8aa3bac72/History.txt (L3)
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53707 b2dd03c8-39d4-4d8f-98ff-823fe69b080e