+#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