Index: src/tls/OFGnuTLSTLSStream.m
==================================================================
--- src/tls/OFGnuTLSTLSStream.m
+++ src/tls/OFGnuTLSTLSStream.m
@@ -27,10 +27,15 @@
 #import "OFTLSHandshakeFailedException.h"
 #import "OFWriteFailedException.h"
 
 int _ObjFWTLS_reference;
 static gnutls_certificate_credentials_t systemTrustCreds;
+
+#ifndef GNUTLS_SAFE_PADDING_CHECK
+/* Some older versions don't have it. */
+# define GNUTLS_SAFE_PADDING_CHECK 0
+#endif
 
 @implementation OFGnuTLSTLSStream
 static ssize_t
 readFunc(gnutls_transport_ptr_t transport, void *buffer, size_t length)
 {