Calculating dependencies ...done!
>>> emerge (1 of 1) media-video/usb-pwc-re-10.0.12_rc1 to /
>>> md5 files   ;-) usb-pwc-re-10.0.12_rc1.ebuild
>>> md5 files   ;-) usb-pwc-re-10.0.11.ebuild
>>> md5 files   ;-) usb-pwc-re-10.0.7.ebuild
>>> md5 files   ;-) files/digest-usb-pwc-re-10.0.12_rc1
>>> md5 files   ;-) files/digest-usb-pwc-re-10.0.11
>>> md5 files   ;-) files/digest-usb-pwc-re-10.0.7
>>> md5 src_uri ;-) pwc-10.0.12-rc1.tar.bz2
 * Determining the location of the kernel source code
 * Found kernel source directory:
 *     /usr/src/linux-2.6.15.1
 * Could not find a Makefile in the kernel source directory.
 * Please ensure that /usr/src/linux points to a complete set of Linux sources

!!! ERROR: media-video/usb-pwc-re-10.0.12_rc1 failed.
!!! Function linux-info_pkg_setup, Line 554, Exitcode 1
!!! Unable to calculate Linux Kernel version
!!! If you need support, post the topmost build error, NOT this status message.