Gentoo update

>>> Emerging (2 of 13) x11-drivers/nvidia-drivers-177.82
 * NVIDIA-Linux-x86-177.82-pkg0.run RMD160 SHA1 SHA256 size ;-) ...                                  [ ok ]
 * checking ebuild checksums ;-) ...                                                                 [ ok ]
 * checking auxfile checksums ;-) ...                                                                [ ok ]
 * checking miscfile checksums ;-) ...                                                               [ ok ]
 * Determining the location of the kernel source code
 * Found kernel source directory:
 *     /usr/src/linux
 * Found sources for kernel version:
 *
 *   ERROR: Kernel configuration is invalid.
 *          include/linux/autoconf.h or include/config/auto.conf are missing.
 *          Run 'make oldconfig && make prepare' on kernel src to fix it.
 *
 * 2.
 *   ERROR: Kernel configuration is invalid.
 *          include/linux/autoconf.h or include/config/auto.conf are missing.
 *          Run 'make oldconfig && make prepare' on kernel src to fix it.
 *
 * 6.
 *   ERROR: Kernel configuration is invalid.
 *          include/linux/autoconf.h or include/config/auto.conf are missing.
 *          Run 'make oldconfig && make prepare' on kernel src to fix it.
 *
 * 27
 *   ERROR: Kernel configuration is invalid.
 *          include/linux/autoconf.h or include/config/auto.conf are missing.
 *          Run 'make oldconfig && make prepare' on kernel src to fix it.
 *
 * -gentoo-r7
/usr/portage/eclass/linux-info.eclass: line 293: [: too many arguments
 * Could not find a usable .config in the kernel source directory.
 * Please ensure that /usr/src/linux points to a configured set of Linux sources.
 * If you are using KBUILD_OUTPUT, please set the environment var so that
 * it points to the necessary object directory so that it might find .config.
 *
 * ERROR: x11-drivers/nvidia-drivers-177.82 failed.
 * Call stack:
 *                      ebuild.sh, line   49:  Called pkg_setup
 *   nvidia-drivers-177.82.ebuild, line  146:  Called linux-mod_pkg_setup
 *               linux-mod.eclass, line  579:  Called require_configured_kernel
 *              linux-info.eclass, line  192:  Called die
 * The specific snippet of code:
 *              die "Kernel not configured; no .config found in ${KV_OUT_DIR}"
 *  The die message:
 *   Kernel not configured; no .config found in /usr/src/linux
 *
 * If you need support, post the topmost build error, and the call stack if relevant.
 * A complete build log is located at '/var/tmp/portage/x11-drivers/nvidia-drivers-177.82/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/x11-drivers/nvidia-drivers-177.82/temp/die.env'.
 *

>>> Failed to emerge x11-drivers/nvidia-drivers-177.82, Log file:

>>>  '/var/tmp/portage/x11-drivers/nvidia-drivers-177.82/temp/build.log'

 * Messages for package x11-drivers/nvidia-drivers-177.82:

 * Could not find a usable .config in the kernel source directory.
 * Please ensure that /usr/src/linux points to a configured set of Linux sources.
 * If you are using KBUILD_OUTPUT, please set the environment var so that
 * it points to the necessary object directory so that it might find .config.
 *
 * ERROR: x11-drivers/nvidia-drivers-177.82 failed.
 * Call stack:
 *                      ebuild.sh, line   49:  Called pkg_setup
 *   nvidia-drivers-177.82.ebuild, line  146:  Called linux-mod_pkg_setup
 *               linux-mod.eclass, line  579:  Called require_configured_kernel
 *              linux-info.eclass, line  192:  Called die
 * The specific snippet of code:
 *              die "Kernel not configured; no .config found in ${KV_OUT_DIR}"
 *  The die message:
 *   Kernel not configured; no .config found in /usr/src/linux
 *
 * If you need support, post the topmost build error, and the call stack if relevant.
 * A complete build log is located at '/var/tmp/portage/x11-drivers/nvidia-drivers-177.82/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/x11-drivers/nvidia-drivers-177.82/temp/die.env'.
 *

 * GNU info directory index is up-to-date.