message: Workaround for borked MPICH headers
diff: @@ -48,8 +48,13 @@ MPIAggregator::IExchangeAbsolutePosition(BufferSTL &bufferSTL, const int step)
  (m_Rank == 0) ? bufferSTL.m_AbsolutePosition
  : bufferSTL.m_AbsolutePosition + bufferSTL.m_Position;
  - CheckMPIReturn(MPI_Isend(&position, 1, ADIOS2_MPI_SIZE_T, destination,
  - 0, m_Comm, &requests[0]),
  + // While the MPI_Isend function should take a const void* as it's first
  + // argument, some MPICH implementations provide a broken signature
  + // which takes a non-const first argument. The explicit const_cast
  + // here works around this.
  + CheckMPIReturn(MPI_Isend(const_cast<size_t *>(&position), 1,
  + ADIOS2_MPI_SIZE_T, destination, 0, m_Comm,
  + &requests[0]),
  ", aggregation Isend absolute position at iteration " +
  std::to_string(step) + "\n");
  }
  