Suppress warnings

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39893 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Add timeout to infinite loop [Bug #8100]

On FreeBSD, it doesn't SEGV.
http://fbsd.rubyci.org/~chkbuild/ruby-trunk/log/20130323T170203Z.log.html.gz

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39894 b2dd03c8-39d4-4d8f-98ff-823fe69b080e