diff --git a/config.h.in b/config.h.in
index a6a2e00..3d8e45a 100644
--- a/config.h.in
+++ b/config.h.in
@@ -12,6 +12,9 @@
 /* Define to 1 if you have the <inttypes.h> header file. */
 #undef HAVE_INTTYPES_H
 
+/* Define to 1 if you have the `gcrypt' library (-lgcrypt). */
+#undef HAVE_LIBGCRYPT
+
 /* Define to 1 if you have the `m' library (-lm). */
 #undef HAVE_LIBM