* 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: app-crypt/truecrypt-4.3a failed.
Call stack:
  ebuild.sh, line 1630:   Called dyn_setup
  ebuild.sh, line 702:   Called qa_call 'pkg_setup'
  ebuild.sh, line 38:   Called pkg_setup
  truecrypt-4.3a.ebuild, line 33:   Called linux-mod_pkg_setup
  linux-mod.eclass, line 464:   Called linux-info_pkg_setup
  linux-info.eclass, line 554:   Called die

!!! Unable to calculate Linux Kernel version