Fortran Interface forces unnecessary export of ANSI filepointer
The C part of the Fortran interface passes a non-null filepointer argument to SIONlib's open functions, causing the fileptr_exported
flag to be set. However, the filepointer value is never actually exported to the Fortran side, because it cannot be used there. This causes unnecessary overhead for synchronising the file poisition (see _sion_update_fileposition
and all of its callers).