libxml2[icu]によってブロックされるqtwebkitの解決

qtwebkitやそれを含んだqt-metaをemergeする際, 次のようなメッセージが出てブロックされてしまうことがあります.

# emerge qtwebkit
[ebuild   R    ] dev-libs/libxml2-2.9.1-r1 USE="python readline"
[ebuild  N     ] dev-qt/qtwebkit-4.8.5 USE="exceptions gstreamer jit"

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

dev-libs/libxml2:2
 
 (dev-libs/libxml2-2.9.1-r1::gentoo, ebuild scheduled for merge) pulled in by
  dev-libs/libxml2:2[!icu?] required by (dev-qt/qtwebkit-4.8.5::gentoo)

 (dev-libs/libxml2-2.91-r1::gentoo, installed) pulled in by
  dev-libs/libxml2:=[icu] required by (www-client/chromium-32.0.1700.77)
  dev-libs/libxml2:2/2=[icu] required by (www-client/chromium-32.0.1700.77)

icuに関する問題とわかるので,フラグの確認を行います.

$ euse -i icu
global use flags (searching: icu) 
[-      ] icu - Enable ICU (Internationalization Components for Unicode) support, using dev-libs/icu 

local use flags (searching: icu) 
no matching entries found 

上記の場合, /etc/portage/make.confのグローバルのUSEフラグにicuを追加すればよいです.

参考文献
Gentoo Forums :: View topic - libxml2[icu] is blocking qt-webkit [SOLVED]