master updated (2476abc -> 0100e33)

[Lars Ingebrigtsen]

larsi pushed a change to branch master.

      from  2476abc   Allow provided-mode-derived-p to work on aliases
       new  cf0869d   Rename the `1value' symbol in testcover.el
       new  0100e33   Warn in message.el when sending encryptable mail


Summary of changes:
 lisp/emacs-lisp/testcover.el | 60 ++++++++++++++++++++++----------------------
 lisp/gnus/message.el         |  4 +++
 lisp/gnus/mml-sec.el         | 15 ++++++-----
 3 files changed, 43 insertions(+), 36 deletions(-)