[macosx] OpenJDK on OS X should use bundled freetype, not one from the system

OpenJDK builds on OS X rely on the freetype linbrary that is installed by X11 on OS X.
That is an optional install, and (if I understand correctly) isn't available at all on
OS X 10.8 (Mountain Lion).
To that end we should make openjdk builds incorporate a freetype lib built
offline direct from mainline freetype sources.
We should further ensure that the freetype_versioncheck uses this and
that tests that trigger freetype run properly.

Finally, we probably should look into making our build systems support
and default to this mode of building.