https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64812
--- Comment #8 from Markus Trippelsdorf <trippels at gcc dot gnu.org> --- Also happens with gcc-5 when linking two different LibreOffice libraries. (libscfiltlo.so and libooxlo.so) The undefined symbol is: x4 ~ # c++filt _ZThn40_N3utl28OSeekableOutputStreamWrapper7acquireEv non-virtual thunk to utl::OSeekableOutputStreamWrapper::acquire() But the symbol is defined in workdir/CxxObject/unotools/source/streaming/streamwrap.o and adding this object file to the link object file list fixes the problem. So it looks like a LibreOffice issue in this case.