A build set can invoke another build set. This allows an 'all'
type build set that builds all the RTEMS archs.
Change the get config call to return a map of paths and files.
Add arch build files. This allows archs to have different versions
and patches for specific tools.
Break the RTEMS config directory up into separate directories to
make long term maintenance easier. This required a change to config.py
to handle the config files being in subdirs of the config directory.
The defaults have been updated to include the install SB root so
packages built before a package are available.
Add makeinfo to the required tools. GDB (and others) need it to
build without error.
Add per arch build sets as this is really what RTEMS needs. You
can then vary the version based on the architecture.
Add '%include' to the buildset files.
