stringio.c: convert arguments just once
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55629 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
stringio.c: convert arguments just once
arguments just once before reading, instead of conversions for
each lines, as r55603.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55629 b2dd03c8-39d4-4d8f-98ff-823fe69b080e