Игнорируются значения указаные в файле /etc/portage/package.mask при обновлении системы через команды emerge -uD world и emerge -uDav world .

barbarian-tux package.mask # cat package 
app-misc/cl-network-meta
app-misc/cl-multimedia-meta
www-client/chromium
net-p2p/deluge
net-ftp/filezilla
net-news/liferea
net-p2p/linuxdcpp
net-misc/pino
net-im/skype
net-irc/xchat
net-im/pidgin
media-video/totem
media-sound/rhythmbox
media-video/cheese
media-gfx/ufraw
app-text/fbreader

barbarian-tux package.mask # emerge -uDav world

 * IMPORTANT: 3 news items need reading for repository 'gentoo'.
 * Use eselect news to read news items.

These are the packages that would be merged, in order:

Calculating dependencies... done!
[binary   R   #] dev-libs/protobuf-2.3.0-r2  USE="python -emacs -examples -java -source -static-libs -vim-syntax"  [0]
[ebuild     UD ] dev-lang/vala-0.8.1 [0.9.3] USE="vapigen -test (-coverage%)" 2,073 kB [0]
[binary  N    #] app-text/fbreader-0.12.10  USE="gtk -debug -qt4"  [0]
[binary  N    #] net-p2p/linuxdcpp-1.0.3  USE="-debug"  [0]
[binary  N    #] net-ftp/filezilla-3.3.4.1  USE="dbus nls -test"  [0]
[binary  N    #] www-client/chromium-9.0.597.94  USE="cups gecko-mediaplayer gnome gnome-keyring -system-sqlite (-system-v8)"  [0]
[ebuild  N    #] net-im/pidgin-2.7.9  USE="dbus gstreamer gtk ncurses networkmanager nls perl python spell startup-notification xscreensaver -debug -doc -eds -gadu -gnutls -groupwise -idn -meanwhile -prediction -qq -sasl -silc -tcl -tk -zephyr -zeroconf" 9,733 kB [0]
[binary  N    #] net-irc/xchat-2.8.8-r1  USE="dbus gtk ipv6 libnotify nls perl python spell ssl -debug -fastscroll (-mmx) -ntlm -tcl -xchatdccserver"  [0]
[binary  N    #] net-news/liferea-1.7.4  USE="dbus libnotify networkmanager -debug"  [0]
[binary  N    #] media-video/totem-2.30.2  USE="bluetooth nsplugin python youtube -debug -doc -galago -iplayer -lirc -nautilus (-tracker)"  [0]
[binary  N    #] media-sound/rhythmbox-0.12.8-r1  USE="cdr gnome-keyring ipod libnotify nsplugin python -daap -debug -doc -hal -lirc -mtp -musicbrainz -test -udev -upnp -webkit"  [0]
[ebuild     UD ] mail-client/thunderbird-3.1.7 [3.1.7-r2] USE="alsa crypt dbus gnome libnotify lightning -bindist -custom-optimization -ldap* -mozdom -startup-notification -system-sqlite -wifi" LINGUAS="bg de en es fr it pl pt_BR ru uk -af -ar -be -bn -bn_BD -ca -cs -da -el -en_GB -en_US -es_AR -es_ES -et -eu -fi -fy -fy_NL -ga -ga_IE -he -hu -id -is -ja -ko -lt -nb -nb_NO -nl -nn -nn_NO -pa -pa_IN -pt -pt_PT -ro -si -sk -sl -sq -sv -sv_SE -tr -zh -zh_CN -zh_TW" 0 kB [0]
[binary  N    #] media-video/cheese-2.30.1  USE="v4l -doc"  [0]
[binary  N    #] net-p2p/deluge-1.3.1  USE="gtk libnotify -webinterface"  [0]
[ebuild     U ~] gnome-extra/gnome-globalmenu-9999 [0.7.10] USE="gnome -debug -test -xfce" 0 kB [1]
[binary  N    #] media-gfx/ufraw-0.16  USE="exif gimp gnome gtk openmp -contrast -hotpixels -lensfun -timezone"  [0]
[ebuild     U  ] dev-java/icedtea6-bin-1.9.6 [1.9.1] USE="X alsa nsplugin -doc -examples -source" 35,107 kB [0]
[binary  N    #] net-im/skype-2.1.0.81  USE="-qt-static"  [0]
[ebuild     UD ] app-emulation/wine-1.2.1 [1.3.13] USE="X alsa cups dbus gecko gphoto2 jpeg mp3 nas ncurses openal opengl oss perl png samba scanner ssl threads truetype win32 win64 xcomposite xinerama xml -capi -custom-cflags (-esd) -fontconfig -gnutls -gsm (-hal) -jack -lcms -ldap -pulseaudio -test (-gstreamer%) (-nls%)" 3,400 kB [0]

Total: 19 packages (2 upgrades, 3 downgrades, 13 new, 1 reinstall, 13 binaries), Size of downloads: 50,311 kB
Portage tree and overlays:
 [0] /usr/portage
 [1] /var/lib/layman/gnome2-globalmenu

!!! The following update has been skipped due to unsatisfied dependencies:

app-emulation/emul-linux-x86-sdl:0

!!! All ebuilds that could satisfy "~app-emulation/emul-linux-x86-baselibs-20110129" have been masked.
!!! One of the following masked packages is required to complete your request:
- app-emulation/emul-linux-x86-baselibs-20110129::gentoo (masked by: package.mask)

(dependency required by "app-emulation/emul-linux-x86-sdl-20110129" [ebuild])
For more information, see the MASKED PACKAGES section in the emerge
man page or refer to the Gentoo Handbook.

Would you like to merge these packages? [Yes/No]