reproduce (this is a W=1 build):
        git remote add jens-wiklander-tee http://git.linaro.org/people/jens.wiklander/linux-tee
        git fetch --no-tags jens-wiklander-tee testing/tuxbuild
        git checkout bc4386e9f6899baeaf60b57076495f2336c1f7f7
        # 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/tee/