(auth-source-protocols)

(auth-source-protocols)
(auth-source-protocols-customize, auth-source-choices): Added and
modified variable customizations and defaults.
(auth-source-pick, auth-source-user-or-password)
(auth-source-protocol-defaults, auth-source-user-or-password-imap)
(auth-source-user-or-password-pop3, auth-source-user-or-password-ssh)
(auth-source-user-or-password-sftp)
(auth-source-user-or-password-smtp): Use new variables and provide an
interface to netrc.el.