reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux.git/commit/?id=7bd52a0d456eef0243f508fc712e59c612ee7d45
        git remote add qcom https://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux
        git fetch --no-tags qcom drivers-for-7.3
        git checkout 7bd52a0d456eef0243f508fc712e59c612ee7d45

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=um olddefconfig
        make W=1 O=build_dir ARCH=um SHELL=/bin/bash