thread.c: suppress warnings [ci skip]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58532 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
thread.c: suppress warnings [ci skip]
suppress warnings when pthread_t is not pointer type.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58532 b2dd03c8-39d4-4d8f-98ff-823fe69b080e