reproduce (this is a W=1 build):
        git checkout ad5c60d66016e544c51ed98635a74073f761f45d
        b4 shazam https://lore.kernel.org/r/20240122-imx-mailbox-v1-2-81413f655210@nxp.com
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/mailbox/