reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm.git/commit/?id=07214aa5c28a2e6d300cbb68e79b002aafedea5d
        git remote add vireshk-pm https://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm.git
        git fetch --no-tags vireshk-pm rust/cpufreq-dt
        git checkout 07214aa5c28a2e6d300cbb68e79b002aafedea5d
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash CLIPPY=1 rustdoc