[Rd] Removing declaration for non-API variable R_NamespaceRegistry

[iuke-tier@ey m@iii@g oii uiow@@edu]

As part of clarifying R's C API for use in packages we are hoping to
remove the declaration of the non-API variable R_NamespaceRegistry
from public header files. If you are using this variable please use
the new function R_getRegisteredNamespace instead for R 4.6.0.

Using a current R-devel you can set -DNO_LEGACY_NONAPI in Makevars and
try to install your package to check if removal of non-API
declarations might affect you.

Best,

luke

-- 
Luke Tierney
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
241 Schaeffer Hall                  email:   luke-tierney using uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu