dev wired ~
$ sudo emerge -v @qt

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

Calculating dependencies... done!
[ebuild   R   ] x11-libs/qt-core-4.6.2-r1  USE="exceptions glib iconv optimized-qmake qt3support ssl (-aqua) -debug -doc -pch" 0 kB
[ebuild   R   ] x11-libs/qt-dbus-4.6.2  USE="exceptions (-aqua) -debug -pch" 0 kB
[ebuild   R   ] x11-libs/qt-sql-4.6.2  USE="exceptions iconv mysql qt3support sqlite (-aqua) -debug (-firebird) -odbc -pch -postgres" 0 kB
[ebuild   R   ] x11-libs/qt-script-4.6.2  USE="exceptions iconv (-aqua) -debug -pch" 0 kB
[ebuild   R   ] x11-libs/qt-xmlpatterns-4.6.2  USE="(-aqua) -debug -pch" 0 kB
[ebuild   R   ] x11-libs/qt-gui-4.6.2  USE="accessibility cups dbus exceptions glib gtk mng qt3support tiff xinerama (-aqua) -debug -nas -nis -pch -raster" 0 kB
[ebuild   R   ] x11-libs/qt-qt3support-4.6.2  USE="accessibility exceptions kde (-aqua) -debug -pch -phonon" 0 kB
[ebuild   R   ] x11-libs/qt-webkit-4.6.2  USE="exceptions kde (-aqua) -debug -pch" 0 kB
[ebuild   R   ] x11-libs/qt-opengl-4.6.2  USE="exceptions qt3support (-aqua) -debug -pch" 0 kB
[ebuild   R   ] x11-libs/qt-svg-4.6.2  USE="exceptions iconv (-aqua) -debug -pch" 0 kB
[ebuild  N    ] x11-libs/qt-assistant-4.6.2  USE="exceptions (-aqua) -debug -pch" 0 kB

Total: 11 packages (1 new, 10 reinstalls), Size of downloads: 0 kB

>>> Recording @qt in "world" favorites file...

>>> Verifying ebuild manifests

>>> Starting parallel fetch

>>> Emerging (1 of 11) x11-libs/qt-core-4.6.2-r1
 * qt-everywhere-opensource-src-4.6.2.tar.gz RMD160 SHA1 SHA256 size ;-) ... [ ok ]
 * checking ebuild checksums ;-) ... [ ok ]
 * checking auxfile checksums ;-) ... [ ok ]
 * checking miscfile checksums ;-) ... [ ok ]
^C

Exiting on signal 2
dev wired ~
$ sudo emerge -av --resume

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

Calculating dependencies... done!
[ebuild   R   ] x11-libs/qt-core-4.6.2-r1  USE="exceptions glib iconv optimized-qmake qt3support ssl (-aqua) -debug -doc -pch" 0 kB
[ebuild   R   ] x11-libs/qt-dbus-4.6.2  USE="exceptions (-aqua) -debug -pch" 0 kB
[ebuild   R   ] x11-libs/qt-script-4.6.2  USE="exceptions iconv (-aqua) -debug -pch" 0 kB
[ebuild   R   ] x11-libs/qt-xmlpatterns-4.6.2  USE="(-aqua) -debug -pch" 0 kB
[ebuild   R   ] x11-libs/qt-sql-4.6.2  USE="exceptions iconv mysql qt3support sqlite (-aqua) -debug (-firebird) -odbc -pch -postgres" 0 kB
[ebuild   R   ] x11-libs/qt-gui-4.6.2  USE="accessibility cups dbus exceptions glib gtk mng qt3support tiff xinerama (-aqua) -debug -nas -nis -pch -raster" 0 kB
[ebuild   R   ] x11-libs/qt-qt3support-4.6.2  USE="accessibility exceptions kde (-aqua) -debug -pch -phonon" 0 kB
[ebuild   R   ] x11-libs/qt-opengl-4.6.2  USE="exceptions qt3support (-aqua) -debug -pch" 0 kB
[ebuild   R   ] x11-libs/qt-svg-4.6.2  USE="exceptions iconv (-aqua) -debug -pch" 0 kB
[ebuild   R   ] x11-libs/qt-webkit-4.6.2  USE="exceptions kde (-aqua) -debug -pch" 0 kB
[ebuild  N    ] x11-libs/qt-assistant-4.6.2  USE="exceptions (-aqua) -debug -pch" 0 kB

Total: 11 packages (1 new, 10 reinstalls), Size of downloads: 0 kB

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