U2F in Firefox on NetBSD

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

We may be a little late to the party, but FYI: I just added support
for U2F security keys (a.k.a. FIDO a.k.a. webauthn, more or less) to
www/firefox and www/firefox68 (current www/firefox-esr) on NetBSD.

https://mail-index.NetBSD.org/pkgsrc-changes/2020/07/15/msg217703.html
https://mail-index.NetBSD.org/pkgsrc-changes/2020/07/15/msg217704.html

It requires kernel support that was only recently added in current and
the netbsd-9 branch, so it won't work in any NetBSD releases yet, but
it will be incorporated in NetBSD 9.1 and NetBSD 10:

https://mail-index.NetBSD.org/source-changes/2020/07/15/msg119401.html
https://mail-index.NetBSD.org/source-changes/2020/03/02/msg114683.html

The devices should just work out of the box once you update your
kernel and firefox: set up your (say) Twitter account to register a
u2f key, and push the button; then when you need to log in later on,
push the button again.  No other setup or state needed.