Undefined PLT symbol "XTRUELENGTH" (Re: R-4.6.0)

[Makoto Fujiwara <makoto%if.t.u-tokyo.ac.jp@localhost>]

R-4.6.0 drops several defintions like XTRUELENGTH,

   https://cran.r-project.org/doc/manuals/r-release/NEWS.pdf
 ---------------
| * These entry points are now marked as hidden and no longer have decla-
| rations in installed header files: ENVFLAGS, EXTPTR_PROT, FRAME, ENCLOS,
| EXTPTR_PTR, EXTPTR_TAG, HASHTAB, IS_S4_OBJECT, LEVELS, NAMED, OBJECT,
| R_shallow_duplicate_attr, Rf_isValidString, Rf_lazy_duplicate,
| Rf_NonNullStringMatch, SETLENGTH, SETLEVELS, SET_BODY, SET_CLOENV,
| SET_ENCLOS, SET_FORMALS, SET_ENVFLAGS, SET_FRAME, SET_GROWABLE_BIT,
| SET_HASHTAB, SET_NAMED, SET_S4_OBJECT, SET_TRUELENGTH, STDVEC_DATAPTR,
| TRUELENGTH, UNSET_S4_OBJECT, XTRUELENGTH.
 ---------------

because of this, several packages fail to package,
Can anyone help me to fix ?

(Following sample is with NetBSD/amd64 9.4)
....
** inst
** byte-compile and prepare package for lazy loading
Error in dyn.load(file, DLLpath = DLLpath, ...) :
  unable to load shared object '/usr/pkg/lib/R/library/rlang/libs/rlang.so':
  /usr/pkg/lib/R/library/rlang/libs/rlang.so: Undefined PLT symbol "XTRUELENGTH" (symnum = 13)
Calls: <Anonymous> ... namespaceImport -> loadNamespace -> library.dynam -> dyn.load
Execution halted
ERROR: lazy loading failed for package 'lifecycle'
* removing '/tmp/devel/R-lifecycle/work/.destdir/usr/pkg/lib/R/library/lifecycle'
*** Error code 1

Stop.
make[1]: stopped in /export/CHROOT/usr/pkgsrc/devel/R-lifecycle
*** Error code 1

Stop.
make: stopped in /export/CHROOT/usr/pkgsrc/devel/R-lifecycle
thinkc-01@makoto 06:48:06/260527(..devel/R-lifecycle)%
--------------

-- 
Makoto Fujiwara
mef%NetBSD.org@localhost
makoto%if.t.u-tokyo.ac.jp@localhost