解决安装KDE4后，安装libreoffice-bin出现的boost，poppler软件包冲突

gentoo上，桌面是kdebase-meta-4.10.5:4，想要安装libreoffice-bin的时候，提示软件包冲突：

sudo emerge libreoffice-bin
Calculating dependencies... done!

<此处省略一大片字符>

!!! Multiple package instances within a single package slot have been pulled
!!! into the dependency graph, resulting in a slot conflict:

dev-libs/boost:0

(dev-libs/boost-1.49.0-r2::gentoo, ebuild scheduled for merge) pulled in by
=dev-libs/boost-1.49* required by (app-office/libreoffice-bin-4.0.4.2::gentoo, ebuild scheduled for merge)

(dev-libs/boost-1.52.0-r6::gentoo, installed) pulled in by
dev-libs/boost:0/1.52= required by (app-office/akonadi-server-1.9.2::gentoo, installed)
>=dev-libs/boost-1.35.0-r5:0/1.52= required by (kde-base/kdepimlibs-4.10.5::gentoo, installed)

app-text/poppler:0

(app-text/poppler-0.22.2-r2::gentoo, ebuild scheduled for merge) pulled in by
app-text/poppler:0/35 required by (app-office/libreoffice-bin-4.0.4.2::gentoo, ebuild scheduled for merge)

(app-text/poppler-0.22.5::gentoo, installed) pulled in by
<app-text/poppler-0.24:0/37=[cxx,jpeg,lcms,tiff,xpdf-headers(+)] required by (net-print/cups-filters-1.0.34-r1::gentoo, installed)

It may be possible to solve this problem by using package.mask to
prevent one of those packages from being selected. However, it is also
possible that conflicting dependencies exist such that they are
impossible to satisfy simultaneously.  If such a conflict exists in
the dependencies of two different packages, then those packages can
not be installed simultaneously. You may want to try a larger value of
the --backtrack option, such as --backtrack=30, in order to see if
that will solve this conflict automatically.

For more information, see MASKED PACKAGES section in the emerge man
page or refer to the Gentoo Handbook.

郁闷，以为libreoffice-bin只能支持gnome桌面，不能支持KDE。难道需要我完全编译libreoffice？！！

<此处省略若干纠结>

最终修改了package.mask

sudo vim /etc/portage/package.mask

# for libreoffice-bin
=dev-libs/boost-1.52.0-r6:0/1.52
=app-text/poppler-0.22.5:0/37

然后：

sudo emerge -1a =dev-libs/boost-1.49.0-r2 poppler

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

Calculating dependencies... done!
[ebuild     UD ] dev-util/boost-build-1.49.0 [1.52.0-r1]
[ebuild  r  UD ] dev-libs/boost-1.49.0-r2 [1.52.0-r6]
[ebuild  r  UD ] app-text/poppler-0.22.2-r2 [0.22.5]
[ebuild  rR    ] net-print/cups-filters-1.0.34-r1
[ebuild  rR    ] app-office/akonadi-server-1.9.2
[ebuild  rR    ] kde-base/kdepimlibs-4.10.5

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

漫长时间的等待，机箱风扇狂响……

解决！

剩下就是emerge libreoffice-bin了