emerge --depclean -p

 * Always study the list of packages to be cleaned for any obvious
 * mistakes. Packages that are part of the world set will always
 * be kept.  They can be manually added to this set with
 * `emerge --noreplace <atom>`.  Packages that are listed in
 * package.provided (see portage(5)) will be removed by
 * depclean, even if they are part of the world set.
 *
 * As a safety measure, depclean will not remove any packages
 * unless *all* required dependencies have been resolved.  As a
 * consequence of this, it often becomes necessary to run
 * `emerge --update --newuse --deep @world` prior to depclean.

Calculating dependencies... done!
 * Dependencies could not be completely resolved due to
 * the following required packages not being installed:
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/kscreen-5.7.5
 *
 *   >=kde-plasma/kde-cli-tools-5.4.1:5 pulled in by:
 *     kde-apps/kmix-16.04.3-r1
 *
 *   >=dev-qt/qtquickcontrols-5.6.1:5[widgets] pulled in by:
 *     kde-plasma/plasma-workspace-5.7.5
 *
 *   net-libs/gnutls:0/0= pulled in by:
 *     net-analyzer/wireshark-2.2.7
 *
 *   >=dev-qt/qtgui-5.6.1:5/5.6= pulled in by:
 *     kde-plasma/plasma-integration-5.7.5
 *
 *   ~media-libs/libmediainfo-0.7.91[-curl,-mms] pulled in by:
 *     media-video/mediainfo-0.7.91
 *
 *   >=kde-plasma/kde-cli-tools-5.5.2:5[kdesu] pulled in by:
 *     sys-block/partitionmanager-2.2.1
 *
 *   >=media-libs/libass-0.9.10:0/5= pulled in by:
 *     media-video/mplayer-1.2.1
 *
 *   >=kde-frameworks/baloo-5.23.0:5 pulled in by:
 *     kde-apps/baloo-widgets-16.04.3
 *
 *   >=kde-frameworks/baloo-5.23.0:5 pulled in by:
 *     kde-apps/gwenview-16.04.3
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/plasma-meta-5.7.5
 *
 *   >=sys-libs/ncurses-5.2-r5:0/5= pulled in by:
 *     sys-boot/grub-2.02_beta3-r1
 *
 *   media-libs/libwebp:0/5= pulled in by:
 *     kde-apps/kimgio-16.04.3
 *
 *   >=net-libs/gnutls-3:0/0=[abi_x86_32(-),abi_x86_64(-)] pulled in by:
 *     net-libs/glib-networking-2.48.2
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/kinfocenter-5.7.5
 *
 *   >=kde-frameworks/kfilemetadata-5.34.0:5 pulled in by:
 *     media-video/plasma-mediacenter-5.7.5
 *
 *   >=kde-apps/kdesu-16.04.3[-handbook] pulled in by:
 *     kde-apps/kdebase-runtime-meta-16.04.3
 *
 *   dev-qt/designer:5 pulled in by:
 *     media-libs/phonon-4.9.0
 *
 *   media-video/ffmpeg:0/54.56.56= pulled in by:
 *     games-emulation/ppsspp-1.4
 *
 *   media-libs/libwebp:0/5= pulled in by:
 *     net-libs/webkit-gtk-2.12.5
 *
 *   media-video/ffmpeg:0/54.56.56=[vaapi] pulled in by:
 *     media-video/vlc-2.2.6
 *
 *   media-video/ffmpeg:0/54.56.56= pulled in by:
 *     media-video/vlc-2.2.6
 *
 *   >=dev-qt/qtimageformats-5.6.1:5 pulled in by:
 *     kde-apps/gwenview-16.04.3
 *
 *   dev-libs/boost:0/1.56.0= pulled in by:
 *     dev-libs/librevenge-0.0.4
 *
 *   dev-libs/icu:0/57= pulled in by:
 *     media-libs/libvisio-0.1.5
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/kscreenlocker-5.7.5
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/oxygen-5.7.5
 *
 *   >=media-video/ffmpeg-2.8.5:0/54.56.56=[abi_x86_32(-),abi_x86_64(-)] pulled in by:
 *     media-plugins/gst-plugins-libav-1.8.3
 *
 *   >=dev-qt/qtgraphicaleffects-5.6.1:5 pulled in by:
 *     kde-plasma/kscreen-5.7.5
 *
 *   >=dev-qt/qtgraphicaleffects-5.6.1:5 pulled in by:
 *     kde-plasma/plasma-desktop-5.7.5
 *
 *   media-video/ffmpeg:0/54.56.56= pulled in by:
 *     media-libs/opencv-2.4.12-r1
 *
 *   >=dev-qt/qtwebkit-5.6.1:5 pulled in by:
 *     kde-plasma/libksysguard-5.7.5
 *
 *   dev-libs/xapian:0/1.2.22= pulled in by:
 *     kde-apps/khelpcenter-16.04.3
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/kde-gtk-config-5.7.5
 *
 *   >=kde-frameworks/kdeclarative-5.34.0:5 pulled in by:
 *     media-video/plasma-mediacenter-5.7.5
 *
 *   >=dev-qt/designer-5.6.1:5 pulled in by:
 *     kde-frameworks/kdesignerplugin-5.26.0
 *
 *   >=media-libs/libass-0.10.2:0/5=[abi_x86_32(-),abi_x86_64(-)] pulled in by:
 *     media-video/ffmpeg-3.2.4
 *
 *   >=kde-frameworks/kfilemetadata-5.23.0:5 pulled in by:
 *     kde-apps/gwenview-16.04.3
 *
 *   >=media-libs/elementary-1.17 pulled in by:
 *     x11-wm/enlightenment-0.20.5
 *
 *   >=media-video/ffmpeg-2.6:0/54.56.56=[vdpau] pulled in by:
 *     media-video/mplayer-1.2.1
 *
 *   >=kde-frameworks/baloo-4.14.3:4[-aqua] pulled in by:
 *     kde-apps/kdepim-common-libs-4.14.11_pre20160211
 *
 *   >=kde-frameworks/kfilemetadata-5.23.0:5 pulled in by:
 *     kde-apps/dolphin-16.04.3
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/powerdevil-5.7.5
 *
 *   >=dev-qt/qtcore-5.6.1:5/5.6= pulled in by:
 *     kde-plasma/kwin-5.7.5
 *
 *   sys-libs/ncurses:0/5= pulled in by:
 *     net-wireless/wpa_supplicant-2.6
 *
 *   >=kde-frameworks/baloo-5.26.0:5 pulled in by:
 *     kde-plasma/plasma-desktop-5.7.5
 *
 *   media-video/ffmpeg:0/54.56.56= pulled in by:
 *     kde-apps/k3b-2.0.3-r5
 *
 *   dev-libs/libical:0/1= pulled in by:
 *     kde-apps/kdepimlibs-4.14.11_pre20160611
 *
 *   dev-libs/boost:0/1.56.0= pulled in by:
 *     net-p2p/qbittorrent-3.1.12
 *
 *   >=kde-plasma/kwallet-pam-5.4.1[oldwallet] pulled in by:
 *     kde-apps/kdebase-runtime-meta-16.04.3
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/breeze-5.7.5
 *
 *   x11-misc/ktsuss pulled in by:
 *     net-misc/wicd-1.7.4-r2
 *
 *   >=kde-plasma/kde-cli-tools-5.4.1:5 pulled in by:
 *     kde-apps/khelpcenter-16.04.3
 *
 *   dev-libs/icu:0/57= pulled in by:
 *     app-text/libebook-0.1.2-r1
 *
 *   >=kde-frameworks/plasma-5.34.0:5 pulled in by:
 *     media-video/plasma-mediacenter-5.7.5
 *
 *   >=dev-qt/qtgraphicaleffects-5.6.1:5 pulled in by:
 *     kde-plasma/plasma-workspace-5.7.5
 *
 *   dev-libs/boost:0/1.56.0= pulled in by:
 *     app-text/libwps-0.4.2
 *
 *   >=kde-frameworks/kactivities-5.34.0:5 pulled in by:
 *     media-video/plasma-mediacenter-5.7.5
 *
 *   ~sys-libs/e2fsprogs-libs-1.42.13 pulled in by:
 *     sys-fs/e2fsprogs-1.42.13
 *
 *   >=kde-frameworks/baloo-5.23.0:5 pulled in by:
 *     kde-apps/dolphin-16.04.3
 *
 *   >=kde-frameworks/kio-5.34.0:5 pulled in by:
 *     media-video/plasma-mediacenter-5.7.5
 *
 *   >=dev-libs/boost-1.46.0:0/1.56.0= pulled in by:
 *     media-video/mkvtoolnix-8.5.2
 *
 *   >=media-libs/libbluray-0.3.0-r1:0/2=[abi_x86_32(-),abi_x86_64(-)] pulled in by:
 *     media-video/ffmpeg-3.2.4
 *
 *   dev-libs/boost:0/1.56.0= pulled in by:
 *     media-sound/ardour-4.2-r1
 *
 *   dev-libs/boost:0/1.56.0= pulled in by:
 *     kde-apps/kdepim-runtime-4.14.11_pre20160211
 *
 *   sys-libs/ncurses:0/5= pulled in by:
 *     media-video/mplayer-1.2.1
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/khotkeys-5.7.5
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/plasma-workspace-5.7.5
 *
 *   >=kde-frameworks/kfilemetadata-5.23.0:5 pulled in by:
 *     kde-apps/baloo-widgets-16.04.3
 *
 *   >=dev-python/sip-4.18:0/11=[python_targets_python2_7(-),python_targets_python3_4(-),-python_single_target_python2_7(-),-python_single_target_python3_4(-),-python_single_target_python3_5(-)] pulled in by:
 *     dev-python/PyQt5-5.7
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/kwin-5.7.5
 *
 *   >=dev-qt/qtwayland-5.6.1:5 pulled in by:
 *     kde-frameworks/kwayland-5.26.0
 *
 *   >=kde-plasma/plasma-workspace-5.9.5:5 pulled in by:
 *     media-video/plasma-mediacenter-5.7.5
 *
 *   >=dev-qt/qtquickcontrols-5.6.1:5 pulled in by:
 *     kde-frameworks/plasma-5.26.0
 *
 *   >=dev-qt/designer-5.6.0:5 pulled in by:
 *     dev-python/PyQt5-5.7
 *
 *   >=media-libs/gegl-0.2.0:0 pulled in by:
 *     media-gfx/gimp-2.8.14-r2
 *
 *   >=dev-libs/icu-3.8.1-r1:0/57= pulled in by:
 *     net-libs/webkit-gtk-2.12.5
 *
 *   >=kde-frameworks/baloo-5.26.0:5 pulled in by:
 *     kde-plasma/plasma-workspace-5.7.5
 *
 *   >=net-libs/gnutls-3.0:0/0= pulled in by:
 *     app-crypt/gnupg-2.1.15
 *
 *   >=media-libs/libass-0.9.8:0/5= pulled in by:
 *     media-video/vlc-2.2.6
 *
 *   dev-libs/sni-qt pulled in by:
 *     kde-plasma/plasma-desktop-5.7.5
 *
 *   dev-libs/icu:0/57= pulled in by:
 *     app-text/libmspub-0.1.2
 *
 *   dev-libs/icu:0/57= pulled in by:
 *     media-libs/libcdr-0.1.1
 *
 *   >=kde-frameworks/baloo-5.34.0:5 pulled in by:
 *     media-video/plasma-mediacenter-5.7.5
 *
 *   dev-libs/boost:0/1.56.0= pulled in by:
 *     dev-cpp/libcmis-0.5.0-r1
 *
 *   app-text/hunspell:0/0= pulled in by:
 *     kde-frameworks/sonnet-5.26.0
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/sddm-kcm-5.7.5
 *
 *   <net-libs/libtorrent-rasterbar-1.0.0 pulled in by:
 *     net-p2p/qbittorrent-3.1.12
 *
 *   >=kde-plasma/kde-cli-tools-5.7.5:5 pulled in by:
 *     kde-plasma/plasma-desktop-5.7.5
 *
 * Have you forgotten to do a complete update prior to depclean? The
 * most comprehensive command for this purpose is as follows:
 *
 *   emerge --update --newuse --deep --with-bdeps=y @world
 *
 * Note that the --with-bdeps=y option is not required in many
 * situations. Refer to the emerge manual page (run `man emerge`)
 * for more information about --with-bdeps.
 *
 * Also, note that it may be necessary to manually uninstall
 * packages that no longer exist in the portage tree, since it may
 * not be possible to satisfy their dependencies.