diff --git a/bin/sh/eval.c b/bin/sh/eval.c
index 347824a8e8e2..51206d931874 100644
--- a/bin/sh/eval.c
+++ b/bin/sh/eval.c
@@ -149,7 +149,7 @@ evalcmd(int argc, char **argv)
  */
 
 void
-evalstring(char *s, int flags)
+evalstring(const char *s, int flags)
 {
 	union node *n;
 	struct stackmark smark;
diff --git a/bin/sh/eval.h b/bin/sh/eval.h
index 4129757e9f01..d4092be45137 100644
--- a/bin/sh/eval.h
+++ b/bin/sh/eval.h
@@ -53,7 +53,7 @@ void reseteval(void);
 #define EV_TESTED 02		/* exit status is checked; ignore -e flag */
 #define EV_BACKCMD 04		/* command executing within back quotes */
 
-void evalstring(char *, int);
+void evalstring(const char *, int);
 union node;	/* BLETCH for ansi C */
 void evaltree(union node *, int);
 void evalbackcmd(union node *, struct backcmd *);
diff --git a/bin/sh/histedit.c b/bin/sh/histedit.c
index c65d1c7134e5..7295c3f003c9 100644
--- a/bin/sh/histedit.c
+++ b/bin/sh/histedit.c
@@ -338,8 +338,8 @@ histcmd(int argc, char **argv __unused)
 				out1fmt("%5d ", he.num);
 			out1str(he.str);
 		} else {
-			char *s = pat ?
-			   fc_replace(he.str, pat, repl) : (char *)he.str;
+			const char *s = pat ?
+			   fc_replace(he.str, pat, repl) : he.str;
 
 			if (sflg) {
 				if (displayhist) {
@@ -477,7 +477,7 @@ bindcmd(int argc, char **argv)
 
 	if (el == NULL)
 		error("line editing is disabled");
-	return (el_parse(el, argc, (const char **)argv));
+	return (el_parse(el, argc, __DECONST(const char **, argv)));
 }
 
 #else
diff --git a/bin/sh/jobs.c b/bin/sh/jobs.c
index b1bfa0944d71..753cf7bd931f 100644
--- a/bin/sh/jobs.c
+++ b/bin/sh/jobs.c
@@ -232,7 +232,7 @@ fgcmd(int argc __unused, char **argv __unused)
 
 
 int
-bgcmd(int argc, char **argv)
+bgcmd(int argc __unused, char **argv __unused)
 {
 	struct job *jp;
 
diff --git a/bin/sh/options.c b/bin/sh/options.c
index 860cf6c645bb..2d0ddce5a3de 100644
--- a/bin/sh/options.c
+++ b/bin/sh/options.c
@@ -465,7 +465,7 @@ getopts(char *optstr, char *optvar, char **optfirst, char ***optnext,
 	int ind = 0;
 	int err = 0;
 	char s[10];
-	const char *optarg = NULL;
+	const char *newoptarg = NULL;
 
 	if ((p = *optptr) == NULL || *p == '\0') {
 		/* Current word is done, advance */
@@ -491,7 +491,7 @@ getopts(char *optstr, char *optvar, char **optfirst, char ***optnext,
 			if (optstr[0] == ':') {
 				s[0] = c;
 				s[1] = '\0';
-				optarg = s;
+				newoptarg = s;
 			}
 			else
 				out2fmt_flush("Illegal option -%c\n", c);
@@ -507,7 +507,7 @@ getopts(char *optstr, char *optvar, char **optfirst, char ***optnext,
 			if (optstr[0] == ':') {
 				s[0] = c;
 				s[1] = '\0';
-				optarg = s;
+				newoptarg = s;
 				c = ':';
 			}
 			else {
@@ -519,7 +519,7 @@ getopts(char *optstr, char *optvar, char **optfirst, char ***optnext,
 
 		if (p == **optnext)
 			(*optnext)++;
-		optarg = p;
+		newoptarg = p;
 		p = NULL;
 	}
 
@@ -527,8 +527,8 @@ getopts(char *optstr, char *optvar, char **optfirst, char ***optnext,
 	if (*optnext != NULL)
 		ind = *optnext - optfirst + 1;
 	*optptr = p;
-	if (optarg != NULL)
-		err |= setvarsafe("OPTARG", optarg, 0);
+	if (newoptarg != NULL)
+		err |= setvarsafe("OPTARG", newoptarg, 0);
 	else {
 		INTOFF;
 		err |= unsetvar("OPTARG");
diff --git a/bin/sh/var.c b/bin/sh/var.c
index def1e0c69ff6..87d7b807727d 100644
--- a/bin/sh/var.c
+++ b/bin/sh/var.c
@@ -141,6 +141,7 @@ static const int locale_categories[7] = {
 static int varequal(const char *, const char *);
 static struct var *find_var(const char *, struct var ***, int *);
 static int localevar(const char *);
+static void setvareq_const(const char *s, int flags);
 
 extern char **environ;
 
@@ -183,7 +184,7 @@ initvar(void)
 			setvareq(*envp, VEXPORT|VTEXTFIXED);
 		}
 	}
-	setvareq("OPTIND=1", VTEXTFIXED);
+	setvareq_const("OPTIND=1", 0);
 }
 
 /*
@@ -389,6 +390,12 @@ setvareq(char *s, int flags)
 }
 
 
+static void
+setvareq_const(const char *s, int flags)
+{
+	setvareq(__DECONST(char *, s), flags | VTEXTFIXED);
+}
+
 
 /*
  * Process a linked list of variable assignments.