[FTBFS] Source eggcups 0.20-0ubuntu4 in Natty

Binary package hint: eggcups

gcc -DDBUS_API_SUBJECT_TO_CHANGE -g -O2 -g -O2 -Wl,-Bsymbolic-functions -o eggcups eggcups-main.o eggcups-ec-marshal.o eggcups-rb-debug.o eggcups-ec-cups-job-monitor.o eggcups-ec-job-model.o eggcups-ec-job-list.o eggcups-ec-tray-icon.o eggcups-eggtrayicon.o eggcups-ec-driver-prompt.o eggcups-ec-driver-prompt-dialog.o -pthread -L/lib /usr/lib/libgnomeui-2.so -lSM -lICE /usr/lib/libbonoboui-2.so /usr/lib/libgnomevfs-2.so /usr/lib/libgnomecanvas-2.so /usr/lib/libgnome-2.so /usr/lib/libpopt.so /usr/lib/libbonobo-2.so /usr/lib/libbonobo-activation.so /usr/lib/libORBit-2.so /usr/lib/libart_lgpl_2.so -lgnome-keyring -ldbus-glib-1 -lgnomecups-1.0 -lgssapi_krb5 /usr/lib/libgnutls.so -lcrypt /usr/lib/libglade-2.0.so /usr/lib/libgtk-x11-2.0.so /usr/lib/libxml2.so /usr/lib/libgdk-x11-2.0.so /usr/lib/libatk-1.0.so /usr/lib/libgio-2.0.so /usr/lib/libpangoft2-1.0.so /usr/lib/libpangocairo-1.0.so -lgdk_pixbuf-2.0 -lm /usr/lib/libcairo.so /usr/lib/libpango-1.0.so /usr/lib/libfreetype.so -lz -lfontconfig /usr/lib/libgobject-2.0.so /usr/lib/libgmodule-2.0.so /usr/lib/libgthread-2.0.so /usr/lib/libgconf-2.so /usr/lib/libglib-2.0.so -lhal -ldbus-1 -lpthread -lrt -L/usr/X11R6/lib -lXss -lcups
/usr/bin/ld: eggcups-eggtrayicon.o: undefined reference to symbol 'XFlush'
/usr/bin/ld: note: 'XFlush' is defined in DSO /usr/lib/libX11.so.6 so try adding it to the linker command line
/usr/lib/libX11.so.6: could not read symbols: Invalid operation
collect2: ld returned 1 exit status
make[3]: *** [eggcups] Error 1
make[3]: Leaving directory `/build/buildd/eggcups-0.20'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/build/buildd/eggcups-0.20'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/build/buildd/eggcups-0.20'
make: *** [debian/stamp-makefile-build] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2