thread.c: check name argument
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52834 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
thread.c: check name argument
string. [ruby-core:71774] [Bug #11756]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52834 b2dd03c8-39d4-4d8f-98ff-823fe69b080e