*
*/
-#ifndef HEADER_DTLS1_H
-#define HEADER_DTLS1_H
+#ifndef HEADER_DTLS1_H
+#define HEADER_DTLS1_H
+
+/* Unless _XOPEN_SOURCE_EXTENDED is defined, struct timeval will not be
+ properly defined with DEC C, at least on VMS */
+#if defined(__DECC) || defined(__DECCXX)
+#define _XOPEN_SOURCE_EXTENDED
+#endif
#include <openssl/buffer.h>
#include <openssl/pqueue.h>