Lock the simulation with a mutex to prevent concurrent access. The C
code being tested uses globals, and can only be run in one context at a
time. The Rust test framework may run tests concurrently, so use the
mutex to prevent this.
Signed-off-by: David Brown <david.brown@linaro.org>
Create a crate `mcuboot-sys` to hold the building and binding of the
mcuboot code. There aren't any substantive code changes here, just
moving the code into a separate crate.
Signed-off-by: David Brown <david.brown@linaro.org>