diff --git a/tools/sexp-conv.c b/tools/sexp-conv.c
index d4b152b673028488d1fabf45b992deafc1dc6ef8..4bdda8c01131b193309ab75a99d5acec0a5c5db4 100644
--- a/tools/sexp-conv.c
+++ b/tools/sexp-conv.c
@@ -23,7 +23,7 @@
  * MA 02111-1307, USA.
  */
 
-#if HAVE_CONFIG_H
+#ifdef HAVE_CONFIG_H
 # include "config.h"
 #endif