[R] update.packages(checkBuilt = TRUE) fails in updating rpanel_1.1-1 due to missing package BWidget

[Juergen Rose]

update.packages(checkBuilt = TRUE) fails with:

> update.packages(checkBuilt = TRUE)
rpanel :
 Version 1.0-6 installed in /usr/lib64/R/library built under R 2.15.0 
 Version 1.1-1 available at http://mirrors.softliste.de/cran
Update (y/N/c)?  y
trying URL
'http://mirrors.softliste.de/cran/src/contrib/rpanel_1.1-1.tar.gz'
Content type 'application/x-gzip' length 702508 bytes (686 Kb)
opened URL
==================================================
downloaded 686 Kb

* installing *source* package ‘rpanel’ ...
** package ‘rpanel’ successfully unpacked and MD5 sums checked
** R
** data
**  moving datasets to lazyload DB
** demo
** inst
** preparing package for lazy loading
Error in structure(.External("dotTcl", ..., PACKAGE = "tcltk"), class =
"tclObj") : 
  [tcl] can't find package BWidget.

Error : unable to load R code in package ‘rpanel’
ERROR: lazy loading failed for package ‘rpanel’
* removing ‘/usr/lib64/R/library/rpanel’
* restoring previous ‘/usr/lib64/R/library/rpanel’

The downloaded source packages are in
        ‘/tmp/RtmpCltR3Z/downloaded_packages’
Updating HTML index of packages in '.Library'
Making packages.html  ... done
Warning message:
In install.packages(update[instlib == l, "Package"], l, contriburl =
contriburl,  :


Installed is tcl-8.6.0-r1 and tk-8.6.0 in a GENTOO environment.