Помогите разобраться с установкой программ

Не понимаю что нужно gentoo для установки пакета, подскажите что почитать или дайте достойный комметарий.

при установке

# emerge virt-manager

выходит сообщение и пакет не ставится

* Last emerge --sync was Fri Jun 28 10:35:01 2013.
Calculating dependencies... done!
[ebuild N ] app-misc/scrub-2.5.2
[ebuild N ] sys-apps/dmidecode-2.11 USE="(-selinux)"
[ebuild N ] app-emulation/spice-protocol-0.12.3
[ebuild N ] x11-libs/gnome-pty-helper-0.34.2 USE="hardened"
[ebuild N ] media-libs/celt-0.5.1.3 USE="ogg -static-libs"
[ebuild NS ] dev-libs/libnl-3.2.21 [1.1.3] USE="-doc -static-libs -utils"
[ebuild N ] net-libs/libssh2-1.4.2 USE="zlib -gcrypt -static-libs {-test}"
[ebuild N ] dev-python/pyparsing-1.5.6 USE="-doc -examples"
[ebuild N ] dev-python/urlgrabber-3.9.1-r1
[ebuild N ] virtual/pyparsing-0 PYTHON_TARGETS="python2_7 (-pypy1_9) -python2_5 -python2_6 -python3_1 -python3_2 (-python3_3)"
[ebuild N ] app-text/xhtml1-20020801-r4
[ebuild N ] dev-libs/yajl-2.0.3
[ebuild N ] dev-perl/Text-CSV-1.210.0 USE="{-test}"
[ebuild N ] net-misc/spice-gtk-0.18 USE="dbus introspection policykit python -doc -gstreamer -gtk3 -pulseaudio -sasl -smartcard -static-libs -usbredir -vala"
[ebuild N ] x11-libs/vte-0.28.2-r204 USE="introspection python -debug -doc -glade"
[ebuild N ] net-libs/gtk-vnc-0.5.1 USE="introspection python -examples -gtk3 -pulseaudio -sasl -vala"
[ebuild N ] dev-python/gnome-python-base-2.28.1
[ebuild N ] dev-python/gconf-python-2.28.1 USE="-examples"
[ebuild N ] net-analyzer/netcat6-1.0-r2 USE="bluetooth ipv6 nls"
[ebuild N ] app-emulation/libvirt-1.0.5.1-r3 USE="caps libvirtd macvtap nfs nls policykit python qemu udev vepa -audit -avahi -firewalld -fuse -iscsi -lvm -lxc -numa -openvz -parted -pcap -phyp -rbd -sasl (-selinux) (-systemd) -uml -virt-network -virtualbox -xen"
[ebuild N ] app-emulation/virtinst-0.600.3
[ebuild N ] app-emulation/virt-manager-0.9.4 USE="policykit spice vnc -gnome-keyring -sasl"

The following USE changes are necessary to proceed:
(see "package.use" in the portage(5) man page for more details)
# required by app-emulation/virt-manager-0.9.4
# required by virt-manager (argument)
=x11-libs/vte-0.28.2-r204 python
# required by app-emulation/virt-manager-0.9.4[vnc]
# required by virt-manager (argument)
=net-libs/gtk-vnc-0.5.1 python
# required by app-emulation/virt-manager-0.9.4[spice]
# required by virt-manager (argument)
>=net-misc/spice-gtk-0.18 python
# required by app-emulation/virt-manager-0.9.4
# required by virt-manager (argument)
=app-emulation/libvirt-1.0.5.1-r3 python

Use --autounmask-write to write changes to config files (honoring
CONFIG_PROTECT). Carefully examine the list of proposed changes,
paying special attention to mask or keyword changes that may expose
experimental or unstable packages.