collapseos/blk/429

( Read one line in input buffer and make IN> point to it )
: (rdln)
    ( EOT or less triggers line flush )
    (infl) BEGIN (rdlnc) 5 < UNTIL
    LF IN( IN> ! ;
( And finally, implement C<* )
: RDLN<
    IN> @ C@
    DUP IF ( not EOL? good, inc and return )
        1 IN> +!
    ELSE ( EOL ? readline. we still return null though )
        (rdln)
    THEN
    ( update C<? flag )
    IN> @ C@ 0 > 0x06 RAM+ !  ( 06 == C<? )
;