diff --git a/contrib/openbsm/bin/auditdistd/token.l b/contrib/openbsm/bin/auditdistd/token.l
index 5e58e8728836..f459013a4453 100644
--- a/contrib/openbsm/bin/auditdistd/token.l
+++ b/contrib/openbsm/bin/auditdistd/token.l
@@ -52,6 +52,7 @@ int depth;
 int lineno;
 
 #define	DP	do { } while (0)
+#define	YY_DECL	int yylex(void)
 %}
 
 %option noinput
diff --git a/usr.bin/ar/acplex.l b/usr.bin/ar/acplex.l
index a82db37f3417..589888e6dc06 100644
--- a/usr.bin/ar/acplex.l
+++ b/usr.bin/ar/acplex.l
@@ -40,6 +40,8 @@ int lineno = 1;
 
 int	yylex(void);
 
+#define	YY_DECL	int yylex(void)
+
 %}
 
 %option nounput
diff --git a/usr.bin/bc/scan.l b/usr.bin/bc/scan.l
index 5d60bb37c232..71cb295956dc 100644
--- a/usr.bin/bc/scan.l
+++ b/usr.bin/bc/scan.l
@@ -46,6 +46,7 @@ static void	 init_strbuf(void);
 static void	 add_str(const char *);
 static int	 bc_yyinput(char *, int);
 
+#define YY_DECL	int yylex(void)
 #define YY_NO_INPUT
 #undef YY_INPUT
 #define YY_INPUT(buf,retval,max) \
diff --git a/usr.bin/m4/tokenizer.l b/usr.bin/m4/tokenizer.l
index da362b4025d1..2b4b2dba3d4f 100644
--- a/usr.bin/m4/tokenizer.l
+++ b/usr.bin/m4/tokenizer.l
@@ -31,6 +31,8 @@ extern int32_t yylval;
 int32_t number(void);
 int32_t parse_radix(void);
 extern int yylex(void);
+
+#define	YY_DECL	int yylex(void)
 %}
 
 delim 	[ \t\n]
diff --git a/usr.bin/mklocale/lex.l b/usr.bin/mklocale/lex.l
index d931df7d45e2..08fa54a4b176 100644
--- a/usr.bin/mklocale/lex.l
+++ b/usr.bin/mklocale/lex.l
@@ -47,6 +47,8 @@ __FBSDID("$FreeBSD$");
 #include "ldef.h"
 #include "y.tab.h"
 #include "extern.h"
+
+#define	YY_DECL	int yylex(void)
 %}
 
 ODIGIT	[0-7]
diff --git a/usr.sbin/bluetooth/bthidd/lexer.l b/usr.sbin/bluetooth/bthidd/lexer.l
index 54821daa3ba1..b9f62a1e7ca2 100644
--- a/usr.sbin/bluetooth/bthidd/lexer.l
+++ b/usr.sbin/bluetooth/bthidd/lexer.l
@@ -37,6 +37,8 @@
 #include "parser.h"
 
 	int	yylex	(void);
+
+#define	YY_DECL	int yylex(void)
 %}
 
 %option yylineno noyywrap nounput noinput
diff --git a/usr.sbin/config/lang.l b/usr.sbin/config/lang.l
index c56c6afebc8a..3e4e11560445 100644
--- a/usr.sbin/config/lang.l
+++ b/usr.sbin/config/lang.l
@@ -93,6 +93,7 @@ unsigned int octal(const char *);
 unsigned int hex(const char *);
 int yyerror(const char *);
 
+#define YY_DECL int yylex(void)
 %}
 
 %option nounput
diff --git a/usr.sbin/jail/jaillex.l b/usr.sbin/jail/jaillex.l
index b77e15a402a5..04de85f2a67a 100644
--- a/usr.sbin/jail/jaillex.l
+++ b/usr.sbin/jail/jaillex.l
@@ -42,6 +42,8 @@ static ssize_t text2lval(size_t triml, size_t trimr, int tovar);
 
 static int instr;
 static int lineno = 1;
+
+#define YY_DECL int yylex(void)
 %}
 
 %option noinput