To support building on older systems, this infrastructure allows
bundling libraries.  At the moment, this is just GLib.

The intent of this system is that a "ostree-embeddeps.tar.gz" is
created, which can be used as input to an RPM or Debian package, which
can then be installed on older operating systems.

To create one, use:

$ cd embedded-dependencies
$ make -f Makefile.bootstrap embedded-deps-download
$ cd ..
$ make release-tarball-embedded

To build it:

$ ./configure --enable-embedded-dependencies ...

as usual.
