emerge -uv pidgin

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

Calculating dependencies... done!
[ebuild     U ] media-libs/gstreamer-0.10.15 [0.10.12] USE="nls%* -debug% -test%" 2,108 kB [0]
[ebuild     U ] net-libs/libgadu-1.7.1 [1.7.0] USE="-ssl -threads" 380 kB [0]
[ebuild     U ] dev-perl/XML-Parser-2.34-r1 [2.34] 225 kB [0]
[ebuild     U ] dev-lang/perl-5.8.8-r4 [5.8.8-r2] USE="berkdb gdbm -build -debug -doc -ithreads -perlsuid" 9,887 kB [0]
[ebuild     U ] dev-libs/glib-2.14.4 [2.12.11] USE="-debug -doc -hardened" 3,273 kB [0]
[ebuild     U ] dev-lang/tcl-8.4.15 [8.4.14] USE="-debug -threads" 3,550 kB [0]
[ebuild     U ] dev-libs/dbus-glib-0.74 [0.73] USE="-debug -doc (-selinux)" 640 kB [0]
[ebuild  N    ] app-admin/python-updater-0.3  3 kB [0]
[ebuild     U ] dev-util/pkgconfig-0.22 [0.21-r1] USE="-hardened" 983 kB [0]
[ebuild     U ] sys-devel/gettext-0.17 [0.16.1] USE="nls -doc -emacs -nocxx" 11,369 kB [0]
[ebuild     U ] dev-db/sqlite-3.4.2 [3.3.12] USE="-debug -doc -nothreadsafe -soundex% -tcl" 2,322 kB [0]
[ebuild     U ] app-crypt/opencdk-0.6.6 [0.5.7] USE="-doc" 471 kB [0]
[ebuild     U ] dev-libs/libxml2-2.6.30 [2.6.28] USE="ipv6 python readline -debug -doc -test" 4,616 kB [0]
[ebuild     U ] dev-libs/libdaemon-0.12 [0.10] USE="-doc" 347 kB [0]
[ebuild     U ] x11-libs/qt-3.3.8-r4 [3.3.8-r2] USE="cups ipv6 xinerama -debug -doc -examples -firebird -gif* -immqt -immqt-bc -mysql -nas -nis -odbc -opengl* -postgres -sqlite" 16,986 kB [0]
[ebuild  NS   ] dev-lang/python-2.5.1-r4  USE="berkdb gdbm ipv6 ncurses readline ssl tk -bootstrap -build -doc -examples -nothreads -sqlite -ucs2" 9,171 kB [0]
[ebuild     U ] dev-lang/tk-8.4.15-r1 [8.4.14] USE="-debug -threads" 3,263 kB [0]
[ebuild     U ] media-libs/gst-plugins-base-0.10.15 [0.10.12] USE="nls%* -debug (-X%*) (-alsa%*) (-esd%*) (-oss%) (-xv%*)" 1,743 kB [0]
[ebuild     U ] net-libs/gnutls-2.0.4 [1.6.2] USE="lzo%* nls zlib -doc -guile%" 4,797 kB [0]
[ebuild     U ] net-dns/avahi-0.6.21 [0.6.18] USE="dbus gdbm gtk howl-compat ipv6%* mdnsresponder-compat mono python qt3 qt4 -autoipd -bookmarks -doc -test" 954 kB [0]
[ebuild     U ] media-libs/gst-plugins-good-0.10.6 [0.10.5] USE="-debug" 1,540 kB [0]
[ebuild     U ] dev-python/dbus-python-0.82.3 [0.80.2] USE="-test%" 477 kB [0]
[ebuild  N    ] net-im/pidgin-2.3.1  USE="bonjour dbus gadu gnutls groupwise gstreamer meanwhile ncurses nls perl prediction qq sasl tk -debug -doc -eds -gtk (-networkmanager) -silc -spell -tcl -zephyr" 9,140 kB [0]
[blocks B     ] <media-libs/gst-plugins-bad-0.10.5 (is blocking media-libs/gst-plugins-good-0.10.6)

Total: 23 packages (20 upgrades, 2 new, 1 in new slot, 1 block), Size of downloads: 88,234 kB
Portage tree and overlays:
 [0] /usr/portage

!!! Error: The above package list contains packages which cannot be installed
!!!        at the same time on the same system.

For more information about Blocked Packages, please refer to the following
section of the Gentoo Linux x86 Handbook (architecture is irrelevant):

http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?full=1#blocked