reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?id=76743359658d730ecba565019069d870d30fe3b8
        git remote add peterz-queue https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git
        git fetch --no-tags peterz-queue x86/ibt
        git checkout 76743359658d730ecba565019069d870d30fe3b8
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=um SUBARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=um SUBARCH=i386 SHELL=/bin/bash