giovanni@localhost ~ $ su -c 'emerge portage'
Parola d'ordine:
Calculating dependencies... done!
>>> Verifying ebuild Manifests...

>>> Emerging (1 of 1) sys-apps/portage-2.1.2.7 to /
 * portage-2.1.2.7.patch.bz2 RMD160 ;-) ...         [ ok ]
 * portage-2.1.2.7.patch.bz2 SHA1 ;-) ...           [ ok ]
 * portage-2.1.2.7.patch.bz2 SHA256 ;-) ...         [ ok ]
 * portage-2.1.2.7.patch.bz2 size ;-) ...           [ ok ]
 * portage-2.1.2.tar.bz2 RMD160 ;-) ...             [ ok ]
 * portage-2.1.2.tar.bz2 SHA1 ;-) ...               [ ok ]
 * portage-2.1.2.tar.bz2 SHA256 ;-) ...             [ ok ]
 * portage-2.1.2.tar.bz2 size ;-) ...               [ ok ]
 * checking ebuild checksums ;-) ...                [ ok ]
 * checking auxfile checksums ;-) ...               [ ok ]
 * checking miscfile checksums ;-) ...              [ ok ]
 * checking portage-2.1.2.tar.bz2 ;-) ...           [ ok ]
 * checking portage-2.1.2.7.patch.bz2 ;-) ...       [ ok ]
>>> Unpacking source...
>>> Unpacking portage-2.1.2.tar.bz2 to /var/tmp/portage/sy
s-apps/portage-2.1.2.7/work
>>> Unpacking portage-2.1.2.7.patch.bz2 to /var/tmp/portag
e/sys-apps/portage-2.1.2.7/work
 * Applying portage-2.1.2.7.patch ...               [ ok ]
 * Setting portage.VERSION to 2.1.2.7 ...           [ ok ]
>>> Source unpacked.
>>> Compiling source in /var/tmp/portage/sys-apps/portage-
2.1.2.7/work/portage-2.1.2 ...
In file included from /usr/include/bits/errno.h:8,
                 from /usr/include/gentoo-multilib/amd64/e
rrno.h:36,
                 from /usr/include/errno.h:8,
                 from tbz2tool.c:8:
/usr/include/gentoo-multilib/amd64/bits/errno.h:25:26: err
or: linux/errno.h: No such file or directory

!!! ERROR: sys-apps/portage-2.1.2.7 failed.
Call stack:
  ebuild.sh, line 1614:   Called dyn_compile
  ebuild.sh, line 971:   Called qa_call 'src_compile'
  ebuild.sh, line 44:   Called src_compile
  portage-2.1.2.7.ebuild, line 86:   Called die

!!! Failed to build tbz2tool
!!! 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/s                                                       ys-apps/portage-2.1.2.7/temp/build.log'.
that the erro i have when i try to upgrade portage.What can i do?