diff --git a/conf/cf-lex.l b/conf/cf-lex.l
index f608a3d3..9e6b120f 100644
--- a/conf/cf-lex.l
+++ b/conf/cf-lex.l
@@ -7,12 +7,15 @@
  */
 
 %{
+#undef REJECT     /* Avoid name clashes */
 
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdarg.h>
 
 #include "nest/bird.h"
+#include "lib/string.h"
 #include "conf/conf.h"
 #include "conf/cf-parse.tab.h"
 
@@ -221,9 +224,16 @@ cf_lex_init_tables(void)
 }
 
 void
-cf_error(char *msg)
+cf_error(char *msg, ...)
 {
-  die(PATH_CONFIG ", line %d: %s", cf_lino, msg);
+  /* FIXME */
+
+  char buf[1024];
+  va_list args;
+
+  va_start(args, msg);
+  bvsprintf(buf, msg, args);
+  die(PATH_CONFIG ", line %d: %s", cf_lino, buf);
 }
 
 void
@@ -243,3 +253,4 @@ cfg_strdup(char *c)
   memcpy(z, c, l);
   return z;
 }
+
diff --git a/conf/conf.h b/conf/conf.h
index 974815a8..1e80628e 100644
--- a/conf/conf.h
+++ b/conf/conf.h
@@ -40,7 +40,7 @@ struct symbol {
 void cf_lex_init_tables(void);
 int cf_lex(void);
 void cf_lex_init(int flag);
-void cf_error(char *msg) NORET;
+void cf_error(char *msg, ...) NORET;
 void cf_allocate(void);
 struct symbol *cf_default_name(char *prefix);