libbb: factor out fflush_stdout_and_exit(EXIT_SUCCESS)

function                                             old     new   delta
fflush_stdout_and_exit_SUCCESS                         -       7      +7
xxd_main                                             890     888      -2
vlock_main                                           353     351      -2
uuencode_main                                        318     316      -2
uniq_main                                            427     425      -2
uname_main                                           250     248      -2
sort_main                                            853     851      -2
shuf_main                                            500     498      -2
route_main                                           238     236      -2
readlink_main                                        113     111      -2
nice_main                                            156     154      -2
last_main                                            957     955      -2
ipcs_main                                            960     958      -2
env_main                                             209     207      -2
chrt_main                                            464     462      -2
cal_main                                             921     919      -2
baseNUM_main                                         650     648      -2
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/16 up/down: 7/-32)            Total: -25 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/nice.c b/coreutils/nice.c
index 28591ac..e70da5d 100644
--- a/coreutils/nice.c
+++ b/coreutils/nice.c
@@ -33,7 +33,7 @@
 
 	if (!*++argv) { /* No args, so (GNU) output current nice value. */
 		printf("%d\n", old_priority);
-		fflush_stdout_and_exit(EXIT_SUCCESS);
+		fflush_stdout_and_exit_SUCCESS();
 	}
 
 	adjustment = 10;  /* Set default adjustment. */