mel-setup-builddir: prompt_choice: check for tty after the # of choices

Signed-off-by: Christopher Larson <kergoth@gmail.com>
mel-setup-builddir: prompt_choice: fix the check of the # of choices

Signed-off-by: Christopher Larson <kergoth@gmail.com>
setup-mel-builddir: ensure we ls the binary dirs, not their contents

Signed-off-by: Christopher Larson <kergoth@gmail.com>