Robert Dietrich

Since nobody reviewed yet, I rebased to have the new _ucp.h_ with `ucp_dt_query` in the branch. I also fixed a bug in the implementation and another issue in the unit...

I squashed the commits and all checks have passed.

I would propose to use https://github.com/LLNL/wrap/blob/fortran-fixes/wrap.py, which addresses this issue also for other MPI implementations.