merge revision(s) 4adb2d655dcd54b28366b4d17e86b21e2b622cd1: [Backport #16738]
Make RbConfig::CONFIG values mutable [Bug #16738] As `RbConfig.expand` modifies the argument and involved `CONFIG` values, its values should be mutable.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_6@67859 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 4adb2d655dcd54b28366b4d17e86b21e2b622cd1: [Backport #16738]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_6@67859 b2dd03c8-39d4-4d8f-98ff-823fe69b080e