line will grow as wide as it needs (glibc starts off at 120),
we can store a narrower view; this also fixes leaks in a few scenarios
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes#12082