Use new-style system-id macros everywhere possible. I hope I haven't

missed any.

This compiles and runs on Linux, and external applications have no
problems with it.  The definite test will be to build this on VMS.

ssl/s2_enc.c

@@ -57,7 +57,7 @@
  */
 
 #include "ssl_locl.h"
-#ifndef NO_SSL2
+#ifndef OPENSSL_NO_SSL2
 #include <stdio.h>
 
 int ssl2_enc_init(SSL *s, int client)
@@ -178,7 +178,7 @@ void ssl2_mac(SSL *s, unsigned char *md, int send)
 	EVP_DigestFinal(&c,md,NULL);
 	/* some would say I should zero the md context */
 	}
-#else /* !NO_SSL2 */
+#else /* !OPENSSL_NO_SSL2 */
 
 # if PEDANTIC
 static void *dummy=&dummy;