Bugzilla Bug 158465

# emerge --update --deep world
Calculating world dependencies /
!!! Ebuilds for the following packages are either all
!!! masked or don't exist:
gnome-extra/gtop net-analyzer/xtraceroute net-analyzer/cheops-ng
net-wireless/gkismet

... done!

>>> Emerging (1 of 1) sys-fs/cowloop-3.0 to /
 * cowloop-3.0.tar.gz MD5 ;-) ...                                         [ ok
]
 * cowloop-3.0.tar.gz RMD160 ;-) ...                                      [ ok
]
 * cowloop-3.0.tar.gz SHA1 ;-) ...                                        [ ok
]
 * cowloop-3.0.tar.gz SHA256 ;-) ...                                      [ ok
]
 * cowloop-3.0.tar.gz size ;-) ...                                        [ ok
]
 * checking ebuild checksums ;-) ...                                      [ ok
]
 * checking auxfile checksums ;-) ...                                     [ ok
]
 * checking miscfile checksums ;-) ...                                    [ ok
]
 * checking cowloop-3.0.tar.gz ;-) ...                                    [ ok
]
 * Determining the location of the kernel source code
 * Found kernel source directory:
 *     /usr/src/linux
 * Found kernel object directory:
 *     /lib/modules/2.6.19-gentoo-r2/build
 * Found sources for kernel version:
 *     2.6.19-gentoo-r2
 * Linux kernel 2.6.19-gentoo-r2
>>> Unpacking source...
>>> Unpacking cowloop-3.0.tar.gz to /var/tmp/portage/sys-fs/cowloop-3.0/work
>>> Source unpacked.
>>> Compiling source in /var/tmp/portage/sys-fs/cowloop-3.0/work/cowloop-3.0/src ...
 * Preparing cowloop module
make: Entering directory `/usr/src/linux-2.6.19-gentoo-r2'
  CC [M]  /var/tmp/portage/sys-fs/cowloop-3.0/work/cowloop-3.0/src/cowloop.o
/var/tmp/portage/sys-fs/cowloop-3.0/work/cowloop-3.0/src/cowloop.c:236:26:
linux/config.h: No such file or directory
/var/tmp/portage/sys-fs/cowloop-3.0/work/cowloop-3.0/src/cowloop.c: In function
`cowlo_writecow':
/var/tmp/portage/sys-fs/cowloop-3.0/work/cowloop-3.0/src/cowloop.c:1507:
warning: passing arg 1 of `vfs_statfs' from incompatible pointer type
/var/tmp/portage/sys-fs/cowloop-3.0/work/cowloop-3.0/src/cowloop.c: In function
`cowlo_openpair':
/var/tmp/portage/sys-fs/cowloop-3.0/work/cowloop-3.0/src/cowloop.c:1814:
warning: passing arg 1 of `vfs_statfs' from incompatible pointer type
make[1]: ***
[/var/tmp/portage/sys-fs/cowloop-3.0/work/cowloop-3.0/src/cowloop.o] Error 1
make: *** [_module_/var/tmp/portage/sys-fs/cowloop-3.0/work/cowloop-3.0/src]
Error 2
make: Leaving directory `/usr/src/linux-2.6.19-gentoo-r2'

!!! ERROR: sys-fs/cowloop-3.0 failed.
Call stack:
  ebuild.sh, line 1580:   Called dyn_compile
  ebuild.sh, line 945:   Called src_compile
  cowloop-3.0.ebuild, line 34:   Called linux-mod_src_compile
  linux-mod.eclass, line 510:   Called die

!!! Unable to make  -C /usr/src/linux
SUBDIRS=/var/tmp/portage/sys-fs/cowloop-3.0/work/cowloop-3.0/src -I. modules.
!!! If you need support, post the topmost build error, and the call stack if
relevant.

*** This bug has been marked as a duplicate of 158463 ***

Dupe.