In _hrempi.c the error handler for MPI was still using the old, deprecated and now removed function MPI_Errhandler_set rather than the new MPI_Comm_set_errhandler. On Ubuntu 20.04 with dependencies installed with the default version of apt this breaks compilation.
In _hrempi.c the error handler for MPI was still using the old, deprecated and now removed function
MPI_Errhandler_setrather than the newMPI_Comm_set_errhandler. On Ubuntu 20.04 with dependencies installed with the default version of apt this breaks compilation.See also: https://www.open-mpi.org/faq/?category=mpi-removed#mpi-1-mpi-errhandler-set