Unmet dependencies

[Delicates]

While trying to emerge this:
[ebuild U ] app-misc/gnome15-0.10.2-r1::gnome15 [0.10.1::gnome15] USE="alsa ayatana* cairo gnome gstreamer lg4l-module lm_sensors systray weather yahoo -debug -fonts -g15 -g19 -g930 -google -imap -pop -pulseaudio -rss -screensaver -telepathy -themes -title -voip -xrandr" PYTHON_TARGETS="python2_7" 0 KiB

Source configuration fails with unmet python dependencies:
...
checking python2.7 module: Xlib... yes
checking python2.7 module: setproctitle... no
configure: WARNING: It is recommend that setproctitle is installed
checking python2.7 module: pyudev... no
checking python2.7 module: pyinputevent... yes
checking python2.7 module: gst... yes
checking python2.7 module: appindicator... no
checking python2.7 module: telepathy... no
checking python2.7 module: alsaaudio... yes
checking python2.7 module: feedparser... yes
checking python2.7 module: vobject... no
checking python2.7 module: gdata.calendar... yes
checking python2.7 module: gdata.analytics... yes
checking python2.7 module: cairoplot... yes
checking python2.7 module: sensors... yes
checking for initLibG15 in -lg15... no
checking for FFTW... yes
checking for PULSE... no
configure: error: Ubuntu indicator cannot be built without appindicator python module

[CMoH]

I have tried to determine dependencies for USE-flag ayatana, but gave up. I think I remember that at the time it was actually masked by the official portage tree.

However, if you can help determine which packages might be needed for this to work, I'd be happy to apply that to this overlay.