• Add XMSS option to enable experimental key support added in 7.7 [1]
• Bring in upstream patches post 7.7 to fix various issues [2]: b81b2d120e9c8a83489e241620843687758925ad - Fix tunnel forwarding broken in 7.7p1 341727df910e12e26ef161508ed76d91c40a61eb - don't kill ssh-agent's listening socket entriely if we fail to accept a connection 85fe48fd49f2e81fa30902841b362cfbb7f1933b - don't free the %C expansion, it's used later for LocalCommand 868afa68469de50d8a43e5daf867d7c624a34d20 - Disable SSH2_MSG_DEBUG messages for Twisted Conch clients f5baa36ba79a6e8c534fb4e0a00f2614ccc42ea6 - Omit 3des-cbc if OpenSSL built without DES

PR: 227758 [1]
Submitted by: IWAMOTO Kouichi <sue@iwmt.org> [1]
PR: 227551 [2]
Reported by: rozhuk.im@gmail.com [2]
Obtained from: upstream mirror https://github.com/openssh/openssh-portable [2]