${BDECFLAGS} work. And fix a real error in the process. A "MAXUSERS"

string could have been passed to free();  There are some warnings here
I am not sure how to fix as they are in the lex scanner code, etc.

usr.sbin/config/Makefile

@@ -3,7 +3,7 @@
 
 PROG=	config
 CFLAGS+=-I. -I${.CURDIR}
-CFLAGS+=-Wall -Wunused -Wmissing-prototypes -Wredundant-decls
+CFLAGS+=${BDECFLAGS}
 SRCS=	config.y main.c lang.l mkmakefile.c mkheaders.c \
 	mkoptions.c y.tab.h
 MAN8=	config.8

usr.sbin/config/config.h

@@ -131,9 +131,9 @@ extern int	hintmode;
 
 char	*get_word(FILE *);
 char	*get_quoted_word(FILE *);
-char	*path(char *);
+char	*path(const char *);
 char	*raisestr(char *);
-void	remember(char *);
+void	remember(const char *);
 void	moveifchanged(const char *, const char *);
 void	newbus_ioconf(void);
 int	yyparse(void);

usr.sbin/config/config.y

@@ -84,7 +84,7 @@ int	maxusers;
 
 #define ns(s)	strdup(s)
 
-static void yyerror(char *s);
+static void yyerror(const char *s);
 
 static char *
 devopt(char *dev)
@@ -283,7 +283,7 @@ Device_spec:
 %%
 
 static void
-yyerror(char *s)
+yyerror(const char *s)
 {
 
 	errx(1, "line %d: %s", yyline + 1, s);

usr.sbin/config/lang.l

@@ -47,7 +47,7 @@
  */
 
 struct kt {
-	char *kt_name;
+	const char *kt_name;
 	int kt_val;
 } key_words[] = {
 	{ "config",	CONFIG },

usr.sbin/config/main.c

@@ -306,7 +306,7 @@ get_quoted_word(FILE *fp)
  * prepend the path to a filename
  */
 char *
-path(char *file)
+path(const char *file)
 {
 	char *cp = NULL;
 
@@ -452,16 +452,15 @@ cleanheaders(char *p)
 }
 
 void
-remember(char *file)
+remember(const char *file)
 {
 	char *s;
 	struct hdr_list *hl;
 
 	if ((s = strrchr(file, '/')) != NULL)
-		s++;
+		s = ns(s + 1);
 	else
-		s = file;
-	s = ns(s);
+		s = ns(file);
 
 	if (index(s, '_') && strncmp(s, "opt_", 4) != 0) {
 		free(s);

usr.sbin/config/mkmakefile.c

@@ -77,7 +77,7 @@ static void do_rules(FILE *);
 static void do_xxfiles(char *, FILE *);
 static void do_objs(FILE *);
 static void do_before_depend(FILE *);
-static int opteq(char *, char *);
+static int opteq(const char *, const char *);
 static void read_files(void);
 
 /*
@@ -281,7 +281,7 @@ read_files(void)
 	struct device *dp;
 	struct device *save_dp;
 	struct opt *op;
-	char *wd, *this, *needs, *special, *depends, *clean, *warn;
+	char *wd, *this, *needs, *special, *depends, *clean, *warning;
 	char fname[MAXPATHLEN];
 	int ddwarned = 0;
 	int nreqs, first = 1, configdep, isdup, std, filetype,
@@ -364,7 +364,7 @@ read_files(void)
 	special = 0;
 	depends = 0;
 	clean = 0;
-	warn = 0;
+	warning = 0;
 	configdep = 0;
 	needs = 0;
 	std = mandatory = 0;
@@ -451,7 +451,7 @@ read_files(void)
 				fname, this);
 			exit(1);
 		}
-		warn = ns(wd);
+		warning = ns(wd);
 		goto nextparam;
 	}
 	nreqs++;
@@ -519,7 +519,7 @@ read_files(void)
 	tp->f_special = special;
 	tp->f_depends = depends;
 	tp->f_clean = clean;
-	tp->f_warn = warn;
+	tp->f_warn = warning;
 	goto next;
 
 doneparam:
@@ -559,14 +559,14 @@ read_files(void)
 	tp->f_special = special;
 	tp->f_depends = depends;
 	tp->f_clean = clean;
-	tp->f_warn = warn;
+	tp->f_warn = warning;
 	if (pf && pf->f_type == INVISIBLE)
 		pf->f_flags |= ISDUP;		/* mark as duplicate */
 	goto next;
 }
 
 static int
-opteq(char *cp, char *dp)
+opteq(const char *cp, const char *dp)
 {
 	char c, d;
 
@@ -725,7 +725,7 @@ do_rules(FILE *f)
 		tp = tail(np);
 		special = ftp->f_special;
 		if (special == 0) {
-			char *ftype = NULL;
+			const char *ftype = NULL;
 			static char cmd[128];
 
 			switch (ftp->f_type) {

usr.sbin/config/mkoptions.c

@@ -92,7 +92,7 @@ options(void)
 	/* Fake MAXUSERS as an option. */
 	op = (struct opt *)malloc(sizeof(*op));
 	memset(op, 0, sizeof(*op));
-	op->op_name = "MAXUSERS";
+	op->op_name = ns("MAXUSERS");
 	snprintf(buf, sizeof(buf), "%d", maxusers);
 	op->op_value = ns(buf);
 	op->op_next = opt;
@@ -117,7 +117,8 @@ options(void)
 static void
 do_option(char *name)
 {
-	char *basefile, *file, *inw;
+	char *file, *inw;
+	const char *basefile;
 	struct opt_list *ol;
 	struct opt *op, *op_head, *topp;
 	FILE *inf, *outf;