upstream: start process of deprecating the -R flag. This was the

old way of performing a remote-to-remote copy that was basically executed scp
on the remote host. It barely worked (needing agent forwarding enabled or
usable credentials on the remote host) and has largely been replaced by a
better SFTP-protocol remote-to-remote copy that runs through the host
performing the copy.

We'll disable this option in a release or two; ok dtucker@

OpenBSD-Commit-ID: dc273300651e581c3db18edf21f2b05ceac60fd7

scp.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: scp.c,v 1.277 2026/09/27 22:39:40 dtucker Exp $ */
+/* $OpenBSD: scp.c,v 1.278 2026/10/01 07:10:56 djm Exp $ */
 /*
  * scp - secure remote copy.  This is basically patched BSD rcp which
  * uses ssh to do the data transfer (instead of using rcmd).
@@ -511,6 +511,8 @@ main(int argc, char **argv)
 			throughlocal = 1;
 			break;
 		case 'R':
+			fprintf(stderr, "warning: remote/remote -R copy mode "
+			    "is deprecated and will soon be removed\n");
 			throughlocal = 0;
 			break;
 		case 'o':