rtems/gcc: Clean up the RSB version message.
config: Default _internal_autotools_path to nil when not an internal build.
darwin: Default to cc and c++ for Mavrick.
sb: Add submodule support to the git support.
sb: Fix downloader url parsing and add submodule git support.

Split the URL by line breaks into separate requests.

With git reset the repo with each run. First perform a hard reset
to remove any local patches and then switch back to master incase
the repo was left on a branch or a detached head.
sb: Do not assume the src is valid.
config: Add support to build qemu.

Qemu requires gettext, glib, libffi, and pixman. DTC is built
as a submodule.

On Mavrick provide a pkg-config command so avoid needing a pkgconfig.
The one here is only just good enough to work.

Provide an internal autotools build including libtool so qemu can
be built from git.