if (smtp_peer_options & OPTION_DSN) argv[i++] = US"-MCD";
if (smtp_peer_options & OPTION_PIPE) argv[i++] = US"-MCP";
if (smtp_peer_options & OPTION_SIZE) argv[i++] = US"-MCS";
if (smtp_peer_options & OPTION_DSN) argv[i++] = US"-MCD";
if (smtp_peer_options & OPTION_PIPE) argv[i++] = US"-MCP";
if (smtp_peer_options & OPTION_SIZE) argv[i++] = US"-MCS";