Otherwise the result is: libtool: link: gcc -o /var/tmp/portage/dev-libs/libunique-1.1.6-r1/work/libunique-1.1.6/unique/tmp-introspectjn1C2n/.libs/Unique-1.0 -O2 -pipe -mtune=itanium2 -g /var/tmp/portage/dev-libs/libunique-1.1.6-r1/work/libunique-1.1.6/unique/tmp-introspectjn1C2n/Unique-1.0.o -Wl,--export-dynamic -pthread -Wl,--export-dynamic -L/var/tmp/portage/dev-libs/libunique-1.1.6-r1/work/libunique-1.1.6/unique ./.libs/libunique-1.0.so -lX11 -lgthread-2.0 -lgmodule-2.0 -lrt -lgtk-x11-2.0 -lgdk-x11-2.0 -lpangocairo-1.0 -latk-1.0 -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lpangoft2-1.0 -lpango-1.0 -lgobject-2.0 -lglib-2.0 -lfreetype -lfontconfig -pthread /usr/lib/gcc/ia64-unknown-linux-gnu/4.7.3/../../../libgdk-x11-2.0.so: undefined reference to `cairo_xlib_surface_create_for_bitmap' /usr/lib/gcc/ia64-unknown-linux-gnu/4.7.3/../../../libgdk-x11-2.0.so: undefined reference to `cairo_xlib_surface_set_size' /usr/lib/gcc/ia64-unknown-linux-gnu/4.7.3/../../../libgdk-x11-2.0.so: undefined reference to `cairo_xlib_surface_create' collect2: error: ld returned 1 exit status
Grepping at sources looks like they don't have any reference to "pango", maybe this is a missing dep of something in libunique DEPEND :/
libunique-1.1.6-r1 RDEPENDs on gtk+:2, which RDEPENDs on cairo[X,svg] So not quite sure how such an error would happen. I presume portage has prevented to have cairo rebuilt with USE=-X and something odd is going on here?
No idea about how to handle this :S
Are you still able to reproduce that problem ? Please update this report with full build.log and emerge --info.