diff --git a/text2pcap-scanner.l b/text2pcap-scanner.l
index 59b571b311..725926df82 100644
--- a/text2pcap-scanner.l
+++ b/text2pcap-scanner.l
@@ -52,6 +52,12 @@ text [^ \n\t]+
 mailfwd >
 eol \r?\n\r?
 
+/* we don't use unput, so don't generate code for it.
+ * This is flex-only, but current thinking is that our lexers don't work
+ * with non-flex anyway...
+ */
+%option nounput
+
 %%
 
 {byte}            { parse_token(T_BYTE, yytext); }