diff --git a/lib/hx509/sel-lex.l b/lib/hx509/sel-lex.l
index 8df78585d..0f0f61bd4 100644
--- a/lib/hx509/sel-lex.l
+++ b/lib/hx509/sel-lex.l
@@ -47,7 +47,6 @@ unsigned lineno = 1;
 static char * handle_string(void);
 static int lex_input(char *, int);
 static void error_message (const char *format, ...);
-void sel_yyerror (char *);
 
 struct hx_expr_input _hx509_expr_input;
 
@@ -92,7 +91,7 @@ error_message (const char *format, ...)
 }
 
 void
-sel_yyerror (char *s)
+_hx509_sel_yyerror (char *s)
 {
     error_message("%s", s);
 }