libbb: introduce and use sleep1()

function                                             old     new   delta
sleep1                                                 -       9      +9
run_shutdown_and_kill_processes                       97      95      -2
restore_state_and_exit                               116     114      -2
reread_partition_table                                67      65      -2
flush_buffer_cache                                    80      78      -2
chat_main                                           1302    1300      -2
timeout_main                                         310     307      -3
telnet_main                                         1235    1232      -3
stop_handler                                          86      83      -3
process_action                                      1078    1075      -3
nbdclient_main                                      1185    1182      -3
init_main                                            789     786      -3
getty_main                                          1541    1538      -3
do_time                                              410     407      -3
runsv_main                                          1682    1677      -5
pause_and_low_level_reboot                            59      54      -5
inetd_main                                          1917    1911      -6
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/16 up/down: 9/-50)            Total: -41 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/slattach.c b/networking/slattach.c
index 51fbc1f..6d2a252 100644
--- a/networking/slattach.c
+++ b/networking/slattach.c
@@ -76,7 +76,7 @@
 	cfsetispeed(&state, B0);
 	cfsetospeed(&state, B0);
 	exitcode |= tcsetattr_serial_or_warn(&state);
-	sleep(1);
+	sleep1();
 
 	/* Restore line status */
 	if (tcsetattr_serial_or_warn(&G.saved_state))