Fix actual reason for linker problems
The actual reason for the linker problems was that the Fortran libraries where listed before the object files, by modifying the _LINK automake variables. The proper way to do is of course to add the necessary libraries after the object files by appending them to the _LDADD variables. As the MPI module was not responsible for the linker problems it is now used by default, unless explicitly switched off with --disable-mpi-module Also, the C test programs that had these linker errors where previously not compiled in the OpenMP case, for no obvious reason. Now they are also included there.