Compatibility with gfortran versions 10+

[emillour]

Recent version of gfortran (10+) are stricter than ever and report as errors "type mismatches" when calls to routines in the same file use different argument types (unless these routines are defined in a module, because then there are explicit interfaces),thus sending a scalar in one place and a 1D-1 element array in another raises and error... hence recent "fixes" such as r2572,r2573,r2577, which are fine workarounds. An alternative is using the "-fallow-argument-mismatch" gfortran option, but this will make gfortran miss cases where there is really a problem...

Still, there remains a problem with calls to MPI routines, e.g.:

/Volumes/ssi_raid2/lmd/gcm/trunk/LMDZ.COMMON/libo/mpigfortran_64x48x49_phymars_para.e/.config/ppsrc/phy_common/mod_phys_lmdz_mpi_transfert.f90:1249:19:

 1249 |     CALL MPI_BCAST(Var,nb,MPI_CHARACTER,mpi_master,COMM_LMDZ_PHY,ierr)
      |                   1
......
 1305 |     CALL MPI_BCAST(Var,nb,MPI_LOGICAL,mpi_master,COMM_LMDZ_PHY,ierr)
      |                   2
Error: Type mismatch between actual argument at (1) and actual argument at (2) (CHARACTER(*)/LOGICAL(4)).

In this case there is no trivial workaround (apart from the "-fallow-argument-mismatch" gfortran option). Moving to using the f90 MPI interface is probably the only way forward.