configure.in: clock_gettime
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42616 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
configure.in: clock_gettime
with different condtion. otherwise -lrt is not linked and the link
fails, after reconfig.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42616 b2dd03c8-39d4-4d8f-98ff-823fe69b080e