Tell users that a rewrite might be a good idea.

util/mkdef.pl

@@ -179,6 +179,7 @@ $crypto.=" crypto/dsa/dsa.h" unless $no_dsa;
 $crypto.=" crypto/dh/dh.h" unless $no_dh;
 $crypto.=" crypto/hmac/hmac.h" unless $no_hmac;
 
+$crypto.=" crypto/engine/engine.h";
 $crypto.=" crypto/stack/stack.h";
 $crypto.=" crypto/buffer/buffer.h";
 $crypto.=" crypto/bio/bio.h";
@@ -622,6 +623,9 @@ sub maybe_add_info {
 	}
 	if ($new_info) {
 		print STDERR "$new_info old symbols got an info update\n";
+		if (!$do_rewrite) {
+			print STDERR "You should do a rewrite to fix this.\n";
+		}
 	} else {
 		print STDERR "No old symbols needed info update\n";
 	}