Without this modification, gfortran throw the following error
if these variables are used for `MPI_DIST_GRAPH_CREATE_ADJACENT` or
`MPI_DIST_GRAPH_CREATE_ADJACENT`.
Error: There is no specific subroutine for the generic
'mpi_dist_graph_create_adjacent' at (1)
only define the unique fortran symbol depending on
- CAPS
- PLAIN
- SINGLE_UNDERSCORE
- DOUBLE_UNDERSCORE
and bind the f08 symbol to the uniquely defined C symbol.
Use real data structures to make the code simpler.
(perl script written by Jeff)