emerge info:
Portage 2.1-r2 (default-linux/amd64/2006.1/desktop, gcc-4.1.1, glibc-2.4-r3, 2.6.17-gentoo-r7 x86_64)
=================================================================
System uname: 2.6.17-gentoo-r7 x86_64 AMD Athlon(tm) 64 Processor 3200+
Gentoo Base System version 1.12.4
ccache version 2.3 [disabled]
app-admin/eselect-compiler: [Not Present]
dev-lang/python:     2.4.3-r1
dev-python/pycrypto: 2.0.1-r5
dev-util/ccache:     2.3
dev-util/confcache:  [Not Present]
sys-apps/sandbox:    1.2.17
sys-devel/autoconf:  2.13, 2.59-r7
sys-devel/automake:  1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6-r2
sys-devel/binutils:  2.16.1-r3
sys-devel/gcc-config: 1.3.13-r3
sys-devel/libtool:   1.5.22
virtual/os-headers:  2.6.11-r2
ACCEPT_KEYWORDS="amd64"
AUTOCLEAN="yes"
CBUILD="x86_64-pc-linux-gnu"
CFLAGS="-march=k8 -O2 -pipe"
CHOST="x86_64-pc-linux-gnu"
CONFIG_PROTECT="/etc"
CONFIG_PROTECT_MASK="/etc/env.d /etc/gconf"
CXXFLAGS="-O2 -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="autoconfig distlocks metadata-transfer sandbox sfperms strict"
GENTOO_MIRRORS="http://distfiles.gentoo.org http://distro.ibiblio.org/pub/linux/distributions/gentoo"
LINGUAS="it"
MAKEOPTS="-j1"
PKGDIR="/usr/portage/packages"
PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --delete-after --stats --timeout=180 --exclude='/distfiles' --exclude='/local' --exclude='/packages'"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
PORTDIR_OVERLAY="/usr/local/portage"
SYNC="rsync://rsync.gentoo.org/gentoo-portage"
USE="amd64 X alsa avi bash-completion berkdb bitmap-fonts cairo cdr cli crypt cups dbus dlloader dri dvd dvdr eds emboss encode fam firefox fortran gdbm gif gpm gstreamer gtk gtk2 hal ipv6 isdnlog jpeg kde libg++ mad mikmod mp3 mpeg ncurses nls nptl nptlonly offensive ogg opengl pam pcre pdflib perl png ppds pppd python qt3 qt4 quicktime readline reflection sdl session spell spl ssl tcpd truetype truetype-fonts type1-fonts udev unicode vorbis xml xorg xv zlib elibc_glibc input_devices_evdev input_devices_keyboard input_devices_mouse input_devices_joystick input_devices_vmmouse kernel_linux linguas_it userland_GNU video_cards_fbdev video_cards_nv video_cards_nvidia video_cards_v4l video_cards_vesa"
Unset:  CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LANG, LC_ALL, LDFLAGS, PORTAGE_RSYNC_EXTRA_OPTS