GUB-OSX 2.13.4

[Graham Percival]

An initial version of 2.13.4, OSX-x86 version, is available at:
http://lilypond.org/~graham/

It's completely untested, and it isn't the real 2.13.4 release,
but it would be awesome if somebody could test it, so anybody
needed it for doc building can continue and stuff.


I hope to get a mingw version later today, although it will
probably be tomorrow.  After that, I'll tackle the generic build
stuff again.

Many thanks to Jan for getting this far!

Cheers,
- Graham