Demo scripts should declare their build-time dependencies, to make
them more user-friendly. If a dependency is not met, users should see
an explicit message rather than an incomprehensible error.
Don't rely on the dependencies of individual programs because some
demo scripts use multiple programs and because some scripts might have
additional requirements.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
The new file programs/demo_common.sh contains initialization code,
utility functions and cleanup code meant to be used by all demo
scripts written in sh.
Initial features:
* msg: Display a message.
* run, run_bad: Run a command, visibly.
* $root_dir, $programs_dir: location of the mbedtls source tree.
* $files_to_clean: files that are cleaned up on exit.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
