sys/cmd/harden: refuse to harden 'read'
sys/cmd/harden: refuse to harden 'read'

Even though 'read' is a regular builtin, hardening 'read' (thereby
turning it into a shell function) is fundamentally broken, because
variable assignments preceding shell function calls persist after
the call on many shells -- so a common and portable idiom like
'IFS="," read -r foo bar baz' would permanently set IFS to ','
(and, on some shells, even export it).

modernish/modernish