diff --git a/lib/config-win32.h b/lib/config-win32.h
index 6aa7f6d1a..04c9ca01e 100644
--- a/lib/config-win32.h
+++ b/lib/config-win32.h
@@ -170,6 +170,9 @@
 /* Define if you have the <winsock.h> header file.  */
 #define HAVE_WINSOCK_H 1
 
+/* Define if you have the <stdlib.h> header file.  */
+#define HAVE_STDLIB_H 1
+
 /* Define if you have the closesocket function.  */
 #define HAVE_CLOSESOCKET 1