io.c: convert arguments just once
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55603 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
io.c: convert arguments just once
just once before reading, instead of conversions for each lines.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55603 b2dd03c8-39d4-4d8f-98ff-823fe69b080e