# emerge -pv qt-gui

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

Calculating dependencies... done!
[ebuild   R   ] x11-libs/qt-gui-4.4.2-r3  USE="accessibility dbus glib mng qt3support tiff -cups -custom-cxxflags -debug -nas -nis -pch -xinerama" INPUT_DEVICES="-wacom" 0 kB

# echo "x11-libs/qt-gui -dbus cups nas -mng" >> /etc/portage/package.use
# emerge -pv qt-gui

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

Calculating dependencies... done!
[ebuild  N    ] app-text/rman-3.2  78 kB
[ebuild  N    ] x11-libs/libXTrap-1.0.0  USE="-debug" 215 kB
[ebuild  N    ] x11-misc/gccmakedep-1.0.2  USE="-debug" 69 kB
[ebuild  N    ] x11-misc/xorg-cf-files-1.0.2  259 kB
[ebuild  N    ] x11-misc/imake-1.0.2  USE="-debug" 111 kB
[ebuild  N    ] media-libs/nas-1.8b  USE="-doc" 1,432 kB
[ebuild   R   ] x11-libs/qt-gui-4.4.2-r3  USE="accessibility cups* glib nas* qt3support tiff -custom-cxxflags -dbus* -debug -mng* -nis -pch -xinerama" INPUT_DEVICES="-wacom" 0 kB

Total: 7 packages (6 new, 1 reinstall), Size of downloads: 2,162 kB
# emerge -DNup world

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

Calculating dependencies... done!
# vim /etc/portage/package.use       //change -dbus to dbus
# emerge -DNupv world

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

Calculating dependencies... done!
[ebuild  N    ] app-text/rman-3.2  78 kB
[ebuild  N    ] x11-libs/libXTrap-1.0.0  USE="-debug" 215 kB
[ebuild  N    ] x11-misc/gccmakedep-1.0.2  USE="-debug" 69 kB
[ebuild  N    ] x11-misc/xorg-cf-files-1.0.2  259 kB
[ebuild  N    ] x11-misc/imake-1.0.2  USE="-debug" 111 kB
[ebuild  N    ] media-libs/nas-1.8b  USE="-doc" 1,432 kB
[ebuild   R   ] x11-libs/qt-gui-4.4.2-r3  USE="accessibility cups* dbus glib nas* qt3support tiff -custom-cxxflags -debug -mng* -nis -pch -xinerama" INPUT_DEVICES="-wacom" 0 kB

Total: 7 packages (6 new, 1 reinstall), Size of downloads: 2,162 kB