Because DEC C - sorry, HP C - is picky about features, we need to
define _XOPEN_SOURCE_EXTENDED to reach fd_set and timeval types and
functionality.

apps/ocsp.c

diff --git a/apps/ocsp.c b/apps/ocsp.c
index 1ae4cf2..6f36edc 100644
--- a/apps/ocsp.c
+++ b/apps/ocsp.c
@@ -57,6 +57,9 @@
  */
 #ifndef OPENSSL_NO_OCSP
 
+#define _XOPEN_SOURCE_EXTENDED	/* So fd_set and friends get properly defined
+				   on OpenVMS */
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>