diff --git a/libguile/ports.c b/libguile/ports.c
index 52a4dee28..52315df09 100644
--- a/libguile/ports.c
+++ b/libguile/ports.c
@@ -43,6 +43,10 @@
 
 /* Headers.  */
 
+#if HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
 #include <stdio.h>
 #include <errno.h>