* lisp/emacs-lisp/ert-x.el (ert-with-temp-file): Accept a new
keyword argument :coding CODING to use as the encoding when
writing initial text to the temporary file.
* test/lisp/mail/undigest-tests.el (rmail-undigest-test-rfc934-digest)
(rmail-undigest-test-rfc1153-digest-strict)
(rmail-undigest-test-rfc1153-less-strict-digest)
(rmail-undigest-test-rfc1153-sloppy-digest)
(rmail-undigest-test-rfc1521-mime-digest)
(rmail-undigest-test-multipart-mixed-digest): Force the temporary
mbox files to have Unix-style EOL format.
Sadly the "temp" in with-temp-file refers to a buffer, not a file.
* test/lisp/mail/undigest-tests.el (rmail-undigest-test-rfc934-digest)
(rmail-undigest-test-rfc1153-digest-strict)
(rmail-undigest-test-rfc1153-less-strict-digest)
(rmail-undigest-test-rfc1153-sloppy-digest)
(rmail-undigest-test-rfc1521-mime-digest)
(rmail-undigest-test-multipart-mixed-digest):
Delete temporary files at end.
* test/lisp/mail/undigest.el: New test file (bug#12873).
* lisp/mail/undigest.el (rmail-digest-methods): Install
rmail-digest-parse-mixed-mime.
(rmail-content-type-boundary): New function, to get a specific
Content-type boundary.
(rmail-digest-parse-mixed-mime): New function, to search for a
multipart/digest message inside a multipart/mixed message.
