provide elpa packages

[David Bremner]

This is an answer to the discussion we were having on irc the other day about easily installing the emacs front-end for a single user.

For users of package.el supporting emacs (iirc, emacs 24.1+), you can

1) make elpa
2) From within emacs M-x package-install-file <return> the-tarball-produced-in-step-1 <return>

That's it, no modifications of paths etc... required.

[PATCH 1/2] build: Move variable definitions to Makefile.global

This looks big, but it's just code movement. Of course with makefiles
moving things around is not without peril, so test builds in various
corner cases (e.g. not current Debian) would be a good idea