FreeCAD seems to suffer from the exact same problem since a couple of days:
[ 15%] Linking CXX shared library ../../lib/libFreeCADGui.so /usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/libQtUiTools.a(quiloader.o): unrecognized relocation (0x2a) in section `.text' /usr/bin/ld: final link failed: Bad value Apparently something changed or is buggy in latest libqt4-dev (which contains libQtUiTools.a). Are you sure that qgis still builds with unstable? It seems to me that all the Qt4 stuff is now at same version between testing and unstable... Probably this bug is actually in one of the Qt4 packages... Cheers Yorik