>>> Emerging (1 of 6) x11-drivers/nvidia-drivers-1.0.9629 to /
 * NVIDIA-Linux-x86-1.0-9629-pkg0.run MD5 ;-) ...                                                      [ ok ] * NVIDIA-Linux-x86-1.0-9629-pkg0.run RMD160 ;-) ...                                                   [ ok ] * NVIDIA-Linux-x86-1.0-9629-pkg0.run SHA1 ;-) ...                                                     [ ok ] * NVIDIA-Linux-x86-1.0-9629-pkg0.run SHA256 ;-) ...                                                   [ ok ] * NVIDIA-Linux-x86-1.0-9629-pkg0.run size ;-) ...                                                     [ ok ] * checking ebuild checksums ;-) ...                                                                   [ ok ] * checking auxfile checksums ;-) ...                                                                  [ ok ] * checking miscfile checksums ;-) ...                                                                 [ ok ] * checking NVIDIA-Linux-x86-1.0-9629-pkg0.run ;-) ...                                                 [ ok ] * Determining the location of the kernel source code
 * Found kernel source directory:
 *     /usr/src/linux
 * 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-1.0.9629 failed.
Call stack:
  ebuild.sh, line 1584:   Called dyn_setup
  ebuild.sh, line 665:   Called pkg_setup
  nvidia-drivers-1.0.9629.ebuild, line 106:   Called linux-mod_pkg_setup
  linux-mod.eclass, line 458:   Called linux-info_pkg_setup
  linux-info.eclass, line 554:   Called die

!!! Unable to calculate Linux Kernel version
!!! If you need support, post the topmost build error, and the call stack if relevant.