Remove NO_IPPORT_RESERVED_CONCEPT

Replace by defining IPPORT_RESERVED to zero on Cygwin, which should have
the same effect without causing problems syncing patches with OpenBSD.
Resync the two affected functions with OpenBSD.  ok djm, sanity checked
by Corinna.
diff --git a/readconf.c b/readconf.c
index c692f7d..d63e596 100644
--- a/readconf.c
+++ b/readconf.c
@@ -294,14 +294,12 @@
 add_local_forward(Options *options, const struct Forward *newfwd)
 {
 	struct Forward *fwd;
-	int i;
-#ifndef NO_IPPORT_RESERVED_CONCEPT
 	extern uid_t original_real_uid;
+	int i;
 
 	if (newfwd->listen_port < IPPORT_RESERVED && original_real_uid != 0 &&
 	    newfwd->listen_path == NULL)
 		fatal("Privileged ports can only be forwarded by root.");
-#endif
 	/* Don't add duplicates */
 	for (i = 0; i < options->num_local_forwards; i++) {
 		if (forward_equals(newfwd, options->local_forwards + i))