diff --git a/lib/libipsec/policy_token.l b/lib/libipsec/policy_token.l
index d648702c5cc..d04720db555 100644
--- a/lib/libipsec/policy_token.l
+++ b/lib/libipsec/policy_token.l
@@ -48,6 +48,7 @@
 
 #include "y.tab.h"
 #define yylval __libipsecyylval	/* XXX */
+#define YY_NO_INPUT
 
 int yylex(void);
 %}