[PATCH v3] emacs: add compatibility functions for emacs 23

[David Bremner]

Mark Walters <markwalters1009 at gmail.com> writes:

> Some of the recent changes to the emacs code have used functions
> introduced in emacs 24. The functions used are read-char-choice and
> setq-local. This changeset adds a file notmuch-compat.el which
> contains compatibility functions so that it should work on emacs
> 23.
>
> Note, since these functions are taken almost unchanged from the emacs
> source they are copyright the Free Software Foundation, and the header
> in the file reflects that.

pushed to master and release