https://lists.mindrot.org/pipermail/openssh-unix-dev/2014-April/032494.html:
> bad bignum encoding for curve25519-sha256@libssh.org
>[...]
> So I screwed up when writing the support for the curve25519 KEX method
> that doesn't depend on OpenSSL's BIGNUM type - a bug in my code left
> leading zero bytes where they should have been skipped. The impact of
> this is that OpenSSH 6.5 and 6.6 will fail during key exchange with a
> peer that implements curve25519-sha256@libssh.org properly about 0.2%
> of the time (one in every 512ish connections).

(cherry picked from commit 5bc265ef454ba0f8d82e8298c3246999fb11a9c8)

Conflicts:
	main/openssh/APKBUILD

(cherry picked from commit c19262f8c5fba86b4a576effe616d72aa3bfe86f)

(cherry picked from commit 4a0cf9bbf7e8ba2d29a213583ad6a157be41616a)

(cherry picked from commit 4c930edc7669ac008cc077cd00afb4a380641581)

- remove usbkbd and usbmouse
- enable NFC

we disable randomize_base on x86 as it seems to break module loading

(cherry picked from commit 54a8932887a08e171e0f9f1d5733992fb1ac5a0b)

(cherry picked from commit 1ab4dbf6662a2f68962800b33a5d13d165b0fdda)

(cherry picked from commit 03fbac2fb3856cefedbb6c5b4c69b5d0d54ec8f5)

and fix build

fixes #3399