thread.c: return the error
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51330 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
thread.c: return the error
failed. fix r51319.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51330 b2dd03c8-39d4-4d8f-98ff-823fe69b080e