I've looked into this bug a bit today and I'd suggest that instead the `mkoctfile-mpi.diff` patch in src:octave (from bug #598227) be modified to be something more like:
-: ${XTRA_CXXFLAGS=%OCTAVE_CONF_XTRA_CXXFLAGS%} +: ${XTRA_CXXFLAGS=-I/usr/include/mpi -DOMPI_SKIP_MPICXX=1 -DMPICH_SKIP_MPICXX=1 %OCTAVE_CONF_XTRA_CXXFLAGS%} That would contain the bug fix to Octave (which is the only place where the bug seems to have surfaced). Normally this is not an issue --- a developer would use mpicc or mpicxx to do the compilation and linking and this would automatically ensure that the correct mpi libraries are used. Octave is broken because it is using g++ and hacking in the MPI include directory without following it up with the necessary link flags. Cheers, Brad