* enum.c: min(n) drops elements bigger than the n-th maximum element.
  (struct nmin_data): New field to record the n-th maximumelement, limit
  (nmin_filter): Update limit field.
  (nmin_i): Drop too big eleents.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47923 b2dd03c8-39d4-4d8f-98ff-823fe69b080e