*: add -Wunused-parameter; fix resulting breakage

function                                             old     new   delta
procps_scan                                         1265    1298     +33
aliascmd                                             278     283      +5
parse_file_cmd                                       116     120      +4
dname_enc                                            373     377      +4
setcmd                                                90      93      +3
execcmd                                               57      60      +3
count_lines                                           72      74      +2
process_command_subs                                 340     339      -1
test_main                                            409     407      -2
mknod_main                                           179     177      -2
handle_incoming_and_exit                            2653    2651      -2
argstr                                              1312    1310      -2
shiftcmd                                             131     128      -3
exitcmd                                               46      43      -3
dotcmd                                               297     294      -3
breakcmd                                              86      83      -3
evalpipe                                             353     349      -4
evalcommand                                         1180    1176      -4
evalcmd                                              109     105      -4
send_tree                                            374     369      -5
mkfifo_main                                           82      77      -5
evalsubshell                                         152     147      -5
typecmd                                               75      69      -6
letcmd                                                61      55      -6
add_cmd                                             1190    1183      -7
main                                                 891     883      -8
ash_main                                            1415    1407      -8
parse_stream                                        1377    1367     -10
alloc_procps_scan                                     55       -     -55
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 7/21 up/down: 54/-148)          Total: -94 bytes
   text    data     bss     dec     hex filename
 797195     658    7428  805281   c49a1 busybox_old
 797101     658    7428  805187   c4943 busybox_unstripped

1 files changed, 5 insertions, 3 deletions

diff --git a/coreutils/tty.c b/coreutils/tty.c
index b0a50ff61..48e15117c 100644
--- a/coreutils/tty.c
+++ b/coreutils/tty.c
@@ -13,7 +13,7 @@
 #include "libbb.h"
 
 int tty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int tty_main(int argc, char **argv)
+int tty_main(int argc, char **argv SKIP_INCLUDE_SUSv2(ATTRIBUTE_UNUSED))
 {
         const char *s;
         USE_INCLUDE_SUSv2(int silent;)  /* Note: No longer relevant in SUSv3. */
@@ -22,15 +22,17 @@ int tty_main(int argc, char **argv)
         xfunc_error_retval = 2; /* SUSv3 requires > 1 for error. */
 
         USE_INCLUDE_SUSv2(silent = getopt32(argv, "s");)
+        USE_INCLUDE_SUSv2(argc -= optind;)
+        SKIP_INCLUDE_SUSv2(argc -= 1;)
 
         /* gnu tty outputs a warning that it is ignoring all args. */
-        bb_warn_ignoring_args(argc - optind);
+        bb_warn_ignoring_args(argc);
 
         retval = 0;
 
         s = ttyname(0);
         if (s == NULL) {
-        /* According to SUSv3, ttyname can on fail with EBADF or ENOTTY.
+        /* According to SUSv3, ttyname can fail with EBADF or ENOTTY.
          * We know the file descriptor is good, so failure means not a tty. */
                 s = "not a tty";
                 retval = 1;