*: 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

diff --git a/shell/msh.c b/shell/msh.c
index 5ed6dfd..63f3659 100644
--- a/shell/msh.c
+++ b/shell/msh.c
@@ -589,7 +589,7 @@
 };
 
 static struct op *scantree(struct op *);
-static struct op *dowholefile(int, int);
+static struct op *dowholefile(int /*, int*/);
 
 
 /* Globals */
@@ -1448,7 +1448,7 @@
 	PUSHIO(afile, f, filechar);
 }
 
-static void onintr(int s)					/* ANSI C requires a parameter */
+static void onintr(int s ATTRIBUTE_UNUSED) /* ANSI C requires a parameter */
 {
 	signal(SIGINT, onintr);
 	intr = 1;
@@ -1864,11 +1864,11 @@
 	return t;
 }
 
-static struct op *dowholefile(int type, int mark)
+static struct op *dowholefile(int type /*, int mark*/)
 {
 	struct op *t;
 
-	DBGPRINTF(("DOWHOLEFILE: enter, type=%d, mark=%d\n", type, mark));
+	DBGPRINTF(("DOWHOLEFILE: enter, type=%d\n", type /*, mark*/));
 
 	multiline++;
 	t = c_list();
@@ -2477,7 +2477,7 @@
 
 		newfile(evalstr(t->op_words[0], DOALL));
 
-		t->left = dowholefile(TLIST, 0);
+		t->left = dowholefile(TLIST /*, 0*/);
 		t->right = NULL;
 
 		outtree = outtree_save;
@@ -3155,7 +3155,7 @@
  * built-in commands: doX
  */
 
-static int dohelp(struct op *t, char **args)
+static int dohelp(struct op *t ATTRIBUTE_UNUSED, char **args ATTRIBUTE_UNUSED)
 {
 	int col;
 	const struct builtincmd *x;
@@ -3191,12 +3191,12 @@
 	return EXIT_SUCCESS;
 }
 
-static int dolabel(struct op *t, char **args)
+static int dolabel(struct op *t ATTRIBUTE_UNUSED, char **args ATTRIBUTE_UNUSED)
 {
 	return 0;
 }
 
-static int dochdir(struct op *t, char **args)
+static int dochdir(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	const char *cp, *er;
 
@@ -3217,7 +3217,7 @@
 	return 1;
 }
 
-static int doshift(struct op *t, char **args)
+static int doshift(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	int n;
 
@@ -3236,7 +3236,7 @@
 /*
  * execute login and newgrp directly
  */
-static int dologin(struct op *t, char **args)
+static int dologin(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	const char *cp;
 
@@ -3251,7 +3251,7 @@
 	return 1;
 }
 
-static int doumask(struct op *t, char **args)
+static int doumask(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	int i;
 	char *cp;
@@ -3301,7 +3301,7 @@
 	return 1;
 }
 
-static int dodot(struct op *t, char **args)
+static int dodot(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	int i;
 	const char *sp;
@@ -3355,7 +3355,7 @@
 	return -1;
 }
 
-static int dowait(struct op *t, char **args)
+static int dowait(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	int i;
 	char *cp;
@@ -3371,7 +3371,7 @@
 	return 0;
 }
 
-static int doread(struct op *t, char **args)
+static int doread(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	char *cp, **wp;
 	int nb = 0;
@@ -3398,12 +3398,12 @@
 	return nb <= 0;
 }
 
-static int doeval(struct op *t, char **args)
+static int doeval(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	return RUN(awordlist, args + 1, wdchar);
 }
 
-static int dotrap(struct op *t, char **args)
+static int dotrap(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	int n, i;
 	int resetsig;
@@ -3484,12 +3484,12 @@
 	return n * m;
 }
 
-static int dobreak(struct op *t, char **args)
+static int dobreak(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	return brkcontin(args[1], 1);
 }
 
-static int docontinue(struct op *t, char **args)
+static int docontinue(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	return brkcontin(args[1], 0);
 }
@@ -3517,7 +3517,7 @@
 	/* NOTREACHED */
 }
 
-static int doexit(struct op *t, char **args)
+static int doexit(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	char *cp;
 
@@ -3533,13 +3533,13 @@
 	return 0;
 }
 
-static int doexport(struct op *t, char **args)
+static int doexport(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	rdexp(args + 1, export, EXPORT);
 	return 0;
 }
 
-static int doreadonly(struct op *t, char **args)
+static int doreadonly(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	rdexp(args + 1, ronly, RONLY);
 	return 0;
@@ -3575,7 +3575,7 @@
 	err(": bad identifier");
 }
 
-static int doset(struct op *t, char **args)
+static int doset(struct op *t ATTRIBUTE_UNUSED, char **args)
 {
 	struct var *vp;
 	char *cp;
@@ -3650,7 +3650,7 @@
 #endif
 }
 
-static int dotimes(struct op *t, char **args)
+static int dotimes(struct op *t ATTRIBUTE_UNUSED, char **args ATTRIBUTE_UNUSED)
 {
 	struct tms buf;
 	unsigned clk_tck = sysconf(_SC_CLK_TCK);