--- libetpan-1.9.3/src/low-level/imap/clientid.c.orig	2019-01-22 16:40:22.000000000 -0300
+++ libetpan-1.9.3/src/low-level/imap/clientid.c	2019-09-25 13:17:29.179525921 -0300
@@ -36,6 +36,7 @@
 #include "mailimap_sender.h"
 #include "clientid_sender.h"
 #include "clientid.h"
+#include <stddef.h>
 
 LIBETPAN_EXPORT
 int mailimap_clientid(mailimap * session,
