slattach: code shrink, better --help text

function                                             old     new   delta
tcsetattr_serial_or_warn                               -      34     +34
static.int_N_SLIP                                      -       4      +4
restore_state_and_exit                               123     117      -6
packed_usage                                       31774   31747     -27
set_termios_state_or_warn                             42       -     -42
slattach_main                                        673     624     -49
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 0/3 up/down: 38/-124)           Total: -86 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/NOFORK_NOEXEC.lst b/NOFORK_NOEXEC.lst
index 9b33afc..3bd82aa 100644
--- a/NOFORK_NOEXEC.lst
+++ b/NOFORK_NOEXEC.lst
@@ -78,7 +78,7 @@
 cp - noexec. runner
 cpio - runner
 crond - daemon
-crontab 0 leaks: open+xasprintf
+crontab - longterm (runs $EDITOR), leaks: open+xasprintf
 cryptpw - noexec. changes state: with --password-fd=N, moves N to stdin
 cttyhack - noexec. spawner
 cut - noexec. runner
@@ -311,7 +311,7 @@
 setlogcons
 setpriv - spawner, changes state, let's play safe and not be noexec
 setserial
-setsid - spawner, uses fork_or_rexec() [not audted to work in noexec], let's play safe and not be noexec
+setsid - spawner, uses fork_or_rexec() [not audited to work in noexec], let's play safe and not be noexec
 setuidgid - noexec. spawner
 sha1sum - noexec. runner
 sha256sum - noexec. runner
@@ -320,7 +320,7 @@
 showkey - interactive, longterm
 shred - runner
 shuf - noexec. runner
-slattach
+slattach - longterm (may sleep forever), uses bb_common_bufsiz1
 sleep - runner, longterm
 smemcap - runner
 softlimit - noexec. spawner