patch: emacs flymake support

[Dave Peticolas]

This patch adds (optional) support for flymake mode
(on-the-fly syntax checking) on Emacs, for UNIX systems.

This work was originally submitted to the Erlware version
of the Emacs mode by Mats Cronqvist.

   http://github.com/jdavisp3/otp/tree/emacs-flymake

dave