automatic definition of the arch file

Context

Following a discussion with Katherine, it appears that editing, coping/pasting examples from a long list of (outdated) arch files to create your own arch file is not the best way to facilitate the access to nemo... 😄

Proposal

I therefore wrote a small script to automatically create the arch file on your machine : build_arch-auto.sh The idea is to automatically guess the proper definition of the paths and compilation options you will need on your machine (a little bit as ./configure does when you compile with the autotools).

build_arch-auto.sh will write the file arch-auto.fcm.
We could imagine that ./makenemo -m auto would automatically calls build_arch-auto.sh if arch-auto.fcm is not existing.

nc-config and h5pcc that are provided with NetCDF and HDF5, are very convenient to get almost the information we need to compile NEMO.
So in an ideal world, it is quite easy to write build_arch-auto.sh... however I tested 3 different machines and realized that the information given back by nc-config and h5pcc can slightly differ and cannot always be used directly to fill the arch file... 😕