test -e include/linux/autoconf.h -a -e include/config/auto.conf || (            \
        echo;                                                           \
        echo "  ERROR: Kernel configuration is invalid.";               \
        echo "         include/linux/autoconf.h or include/config/auto.conf are missing.";      \
        echo "         Run 'make oldconfig && make prepare' on kernel src to fix it.";  \
        echo;                                                           \
        /bin/false)