* installing *source* package ‘loon’ ...
** this is package ‘loon’ version ‘1.4.3’
** using staged installation
=== Checking Tcl/Tk version (≥ 8.6 and < 9.0) ===
→ Could not detect Tcl/Tk via Rscript; falling back to system tclsh
./configure: 45: Syntax error: redirection unexpected
ERROR: configuration failed for package ‘loon’
* removing ‘/srv/hornik/tmp/CRAN_pretest/loon.Rcheck/loon’