Hi all,

I would like to deprecate three C-API functions (more may come later)
in https://github.com/numpy/numpy/pull/15427

The functions are:
  * PyArray_GetArrayParamsFromObject
  * PyUfunc_GenericCall
  * PyUFunc_SetUsesArraysAsData

I could not find downstream usage for any of these and they seem useful
only on first glance to me.

The first one is too complex (regarding scalars), simply converting to
an array first should be just as well.
The second one is almost identical to `PyObject_Call`. And the third
one is not even documented and while the idea is sound, I am not sure
that there are any cases where it is useful [0]

My idea is to add the deprecation warning now, and if nobody notices it
remove them as soon as 1.19 is released.