update benz
update benz (improve compliance)
update benz (remove type-punning)
update benz (suppress more warnings)
WIP: Add (picrin socket) and (srfi 106).

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
Prefix % to the names of private items.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>