Use a mutex to make SortedSet.setup thread-safe
This should fix [Bug #13735].
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60304 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Use a mutex to make SortedSet.setup thread-safe
This should fix [Bug #13735].
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60304 b2dd03c8-39d4-4d8f-98ff-823fe69b080e