[PROJ] Equivalent of OSRSetFromUserInput in proj 6 API

[Nyall Dawson]

Hi list,

While plugging away at the QGIS proj 6 upgrade I came across code
which uses OSRSetFromUserInput in order to convert any freeform string
to a coordinate reference system object.

Is there an equivalent of this in the proj 6 API I should be using
instead of this?

Nyall