* mh-compat.el (mh-define-obsolete-variable-alias)

* mh-compat.el (mh-define-obsolete-variable-alias)
(mh-make-obsolete-variable): New macros to fix XEmacs compiler
warnings.

* mh-letter.el (mh-yank-hooks): Use new mh-make-obsolete-variable
macro.

* mh-e.el (mh-kill-folder-suppress-prompt-hooks): Use new
mh-define-obsolete-variable-alias macro.

* mh-compat.el (mh-cl-flet): New alias for cl-flet on Emacs 24 and
flet elsewhere.

* mh-thread.el (mh-thread-set-tables): Replace flet with new alias
mh-cl-flet.

* mh-show.el (mh-gnus-article-highlight-citation): Replace flet with
new alias mh-cl-flet.

* mh-mime.el (mh-display-with-external-viewer, mh-mime-display)
(mh-press-button, mh-push-button, mh-display-emphasis): Replace flet
with new alias mh-cl-flet.

* mh-e.el (mh-invisible-header-fields-internal): Remove trailing
  whitespace.