recognise HEARTBEATS in mkdef.pl script
diff --git a/util/mkdef.pl b/util/mkdef.pl
index efef49d..13cf2aa 100755
--- a/util/mkdef.pl
+++ b/util/mkdef.pl
@@ -101,7 +101,7 @@
 			 # RFC3779
 			 "RFC3779",
 			 # TLS
-			 "TLSEXT", "PSK", "SRP",
+			 "TLSEXT", "PSK", "SRP", "HEARTBEATS",
 			 # CMS
 			 "CMS",
 			 # CryptoAPI Engine