With an update of digikam (from 4.12 to 4.14) comes an update of opencv (from 2.4.10 to 3.0.0).

But opencv-3.0.0 cannot be build because it complains that there are 2 python versions specified via PYTHON_SINGLE_TARGET. But emerge --info shows that this is not so.

~ # emerge --info
Portage 2.2.20.1 (python 3.3.5-final-0, funtoo/1.0/linux-gnu/arch/x86-64bit, gcc-4.9.3, glibc-2.20-r2, 3.19.3-1~exp1 x86_64)
=================================================================
System uname: Linux-3.19.3-1~exp1-x86_64-Intel-R-Core-TM-_i5-5250U_CPU@_1.60GHz-with-gentoo-2.2.0
KiB Mem: 16319820 total, 13222920 free
KiB Swap: 16777212 total, 16777212 free
sh bash 4.3_p39-r1
ld GNU ld (Funtoo 2.25) 2.25.0
app-shells/bash: 4.3_p39-r1::gentoo
dev-java/java-config: 2.2.0::gentoo
dev-lang/perl: 5.22.0::gentoo
dev-lang/python: 2.7.10::gentoo, 3.3.5-r2::gentoo
dev-util/cmake: 3.3.2-r1::gentoo
sys-apps/baselayout: 2.2.0-r6::gentoo
sys-apps/openrc: 0.12.4-r4::gentoo
sys-apps/sandbox: 2.9::gentoo
sys-devel/autoconf: 2.13::gentoo, 2.69-r1::gentoo
sys-devel/automake: 1.11.6-r1::gentoo, 1.13.4::gentoo, 1.14.1::gentoo, 1.15::gentoo
sys-devel/binutils: 2.25-r2::gentoo
sys-devel/gcc: 4.9.3::gentoo
sys-devel/gcc-config: 1.8::gentoo
sys-devel/libtool: 2.4.6-r1::gentoo
sys-devel/make: 4.1-r1::gentoo
sys-kernel/linux-headers: 4.0::gentoo (virtual/os-headers)
sys-libs/glibc: 2.20-r2::gentoo
Repositories:

gentoo
location: /usr/portage
sync-type: git
sync-uri: git://github.com/funtoo/ports-2012.git
priority: -1000

Installed sets: @kdv-kde-applications, @kdv-kde-baseapps
ACCEPT_KEYWORDS="amd64 ~amd64"
ACCEPT_LICENSE="* -@EULA Oracle-BCLA-JavaSE"
CBUILD="x86_64-pc-linux-gnu"
CFLAGS="-march=broadwell -O2 -pipe"
CHOST="x86_64-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/lib64/libreoffice/program/sofficerc /usr/share/config /usr/share/gnupg/qualified.txt"
CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/dconf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo"
CXXFLAGS="-march=broadwell -O2 -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="assume-digests binpkg-logs config-protect-if-modified distlocks ebuild-locks fixlafiles merge-sync news parallel-fetch preserve-libs protect-owned sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync xattr"
FFLAGS="-march=broadwell -O2 -pipe"
GENTOO_MIRRORS="http://distfiles.gentoo.org"
LANG="en_US.UTF-8"
LDFLAGS="Wl,-O1 -Wl,sort-common -Wl,-as-needed"
MAKEOPTS="-j5"
PKGDIR="/usr/portage/packages"
PORTAGE_CONFIGROOT="/"
PORTAGE_TMPDIR="/var/tmp"
USE="X a52 aac acl alsa amd64 apng berkdb bluray bzip2 cdda cddb cdio cdr consolekit cracklib crypt cups cxx dbus dri dts dvd dvdr dvdread encode exif faac faad ffmpeg flac gdbm gif gimp gpm ico iconv icu ieee1394 ios ipod ipv6 jpeg jpeg2k kde lame libass libguess libmpeg2 mad matroska mjpeg mmx modules mp3 mpeg mtp mudflap multilib ncurses networkmanager nls nptl nsplugin ogg opengl openmp pam pcre pdf png policykit postproc pppd python qt5 quicktime readline resolvconf samba scanner sndfile sse sse2 ssl svg syslog taglib tcpd theora tiff truetype twolame udev udisks unicode upower v4l vorbis vpx wav wavpack webp win32codecs wmf x264 x265 xattr xml xvid zlib" ABI_X86="64" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel ice1724 intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" ALSA_PCM_PLUGINS="adpcm alaw asym copy dmix dshare dsnoop empty extplug file hooks iec958 ioplug ladspa lfloat linear meter mmap_emul mulaw multi null plug rate route share shm softvol" APACHE2_MODULES="actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias authn_core authz_core socache_shmcb unixd" CALLIGRA_FEATURES="kexi words flow plan sheets stage tables krita karbon braindump author" CAMERAS="ptp2" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" CPU_FLAGS_X86="aes avx fma3 mmx mmxext popcnt sse sse2 sse3 sse4_1 sse4_2 ssse3" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf superstar2 timing tsip tripmate tnt ublox ubx" GRUB_PLATFORMS="efi-64 pc" INPUT_DEVICES="evdev" KERNEL="linux" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php5-5" PYTHON_ABIS="2.7 3.3" PYTHON_SINGLE_TARGET="python3_3" PYTHON_TARGETS="python2_7 python3_3" QEMU_SOFTMMU_TARGETS="i386 x86_64" QEMU_USER_TARGETS="i386 x86_64" RUBY_TARGETS="ruby20 ruby21 ruby22" SANE_BACKENDS="hp" USERLAND="GNU" VIDEO_CARDS="intel i965" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account"
Unset: CPPFLAGS, CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LC_ALL, LINGUAS, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS

en

~ # emerge -1uDavN digikam

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

Calculating dependencies... done!

!!! The ebuild selected to satisfy ">=media-libs/opencv-3.0.0[contrib]" has unmet requirements.

• media-libs/opencv-3.0.0::gentoo USE="eigen ffmpeg ieee1394 jpeg jpeg2k opengl openmp png python qt5 tiff v4l -contrib -cuda -doc -examples -gstreamer -gtk (-ipp) -java (-libav) -opencl -openexr -pch -qt4 -testprograms -threads -vtk -xine" PYTHON_SINGLE_TARGET="python2_7 python3_3 -python3_4" PYTHON_TARGETS="python2_7 python3_3 -python3_4"

The following REQUIRED_USE flag constraints are unsatisfied:
python? ( exactly-one-of ( python_single_target_python3_3 python_single_target_python3_4 python_single_target_python2_7 ) )

The above constraints are a subset of the following complete expression:
python? ( exactly-one-of ( python_single_target_python3_3 python_single_target_python3_4 python_single_target_python2_7 ) python_single_target_python3_3? ( python_targets_python3_3 ) python_single_target_python3_4? ( python_targets_python3_4 ) python_single_target_python2_7? ( python_targets_python2_7 ) ) qt4? ( !qt5 ) qt5? ( !qt4 )

(dependency required by "media-gfx/digikam-4.14.0::gentoo" [ebuild])
(dependency required by "digikam" [argument])