diff --git a/common/rfb/CSecurityTLS.cxx b/common/rfb/CSecurityTLS.cxx
index 446674f..8840868 100644
--- a/common/rfb/CSecurityTLS.cxx
+++ b/common/rfb/CSecurityTLS.cxx
@@ -42,6 +42,7 @@
 #include <rdr/TLSInStream.h>
 #include <rdr/TLSOutStream.h>
 #include <os/os.h>
+#include <os/print.h>
 
 #include <gnutls/x509.h>