Redo `in-port' and `in-lines' using `in-producer', since this gives us a faster macro version for the loops.
Redo `in-port' and `in-lines' using `in-producer', since this gives us a
faster macro version for the loops.

svn: r16474

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket