diff --git a/acl-scanner.l b/acl-scanner.l
index 98442e6..ea5f1a7 100644
--- a/acl-scanner.l
+++ b/acl-scanner.l
@@ -19,6 +19,7 @@
  */
 
 #include <ctype.h>
+#define YY_NO_INPUT
 #include "acl-parser.h"
 %}
 
diff --git a/librfc822/address_scan.l b/librfc822/address_scan.l
index 290e251..58b9b33 100644
--- a/librfc822/address_scan.l
+++ b/librfc822/address_scan.l
@@ -30,6 +30,7 @@ extern int     yylval;
 char *         rfc822_address_buffer;
 int            rfc822_address_buffer_pos;
 
+#define YY_NO_INPUT
 #define YY_INPUT(buf,result,max_size) { \
     buf[0] = rfc822_address_buffer[rfc822_address_buffer_pos++]; \
     result = ((buf[0] != '\0') ? 1 : YY_NULL); \