musl: version 1.0.0

NB: This currently doesn't add a working musl-wrapper around musl-gcc to
allow it to work properly (musl has its own dynamic linker as well as
libc too which must be accounted for). But at the moment it builds fine,
and I plan on working more on it in the future. So lets get it
integrated and building on Hydra.

Signed-off-by: Austin Seipp <aseipp@pobox.com>