Configure snippet is not truly able to manage both netcdf3 and netcdf4

[frankie]

When testing nc_open it does not consider that netcdf4 can be built with --enable-netcdf-4. In this case netcdf requires linking HDF5 and libz. Netcdf now offers a pkg-config snippet to manage properly linking. On sid it returns currently:

-L/usr -lnetcdf -lhdf5_hl -lhdf5 -lz

There are different ways to support both netcdf3/traditional builds or the new one. It's up to you decide if splitting --with-netcdf3/4 is appropriate or having a try with pkg-config would be a better option.