Quentin 09/07/2021 compilation was not possible with MNH_ECRAD not defined and VER_ECRAD=140 (default option without MNH_ECRAD)

Juan 6/05/2021: move build of eccode to OBJDIR_MASTER <-> better management of different compiler version

Juan 27/04/2021:Makefile.MESONH.mk , move netcdf lib to OBJDIR_MASTER for better management in case of recompilation with different compiler version

This is incomplete for the moment. MesoNH must always be compiled with this key for the time being.

(cherry picked from commit 0f6a75e7)

Philippe 15/03/2019: use MNHINT_MPI and MNHREAL_MPI from modd_precision, remove MNH_MPI_DOUBLE_PRECISION and MNH_MPI_RANK_KIND keywords

* always set MNH_REAL (8 by default)
* MNH_REAL has to be set to 4 or 8 (and not R4 or R8)
* XYZ is slightly modified to contain ...-ARCH-RxIy-...
* pass MNH_REAL to pre-processing
* replace MNH_REALS by MNH_REAL

* HDF5 1.8.9 -> 1.8.20
* netCDF 4.1.3 -> 4.5.0
* netCDF-fortran 4.1.3 -> 4.4.4
* added libaec 0.3.2 (equivalent to szlib but without licence problems)