MacOS – How to troubleshoot R and tk on macOS

I am getting warnings and empty popup boxes when compiling and loading R packages that depend on tk. They say that tk was not installed correctly.

I am using homebrew, but I can't tell which package might provide a correct install of tk, or if it would conflict with the existing (but broken) installation.

What is the recommended way to install enough of tk on OSX so that an R package with tk as a dependency (e.g. RNCEP) R will compile without giving this warning?

Update

Here is the warning that I get when trying to load an R package that depends on tk.tcl:

Warning message:
In fun(libname, pkgname) :
  Can't find a usable tk.tcl in the following directories: 
    /System/Library/Frameworks/Tcl.framework/Versions/8.5/Resources/Scripts/tk8.5

/System/Library/Frameworks/Tcl.framework/Versions/8.5/Resources/Scripts/tk8.5/Resources/Scripts
/System/Library/Frameworks/Tcl.framework/Versions/8.5/Resources/tk8.5
/System/Library/Frameworks/Tcl.framework/Versions/8.5/Resources/tk8.5/Resources/Scripts
./lib/tk8.5 ./lib/tk8.5/Resources/Scripts ~/Library/Tcl/tk8.5
~/Library/Tcl/tk8.5/Resources/Scripts /Library/Tcl/tk8.5
/Library/Tcl/tk8.5/Resources/Scripts /System/Library/Tcl/tk8.5
/System/Library/Tcl/tk8.5/Resources/Scripts
/System/Library/Tcl/8.5/tk8.5
/System/Library/Tcl/8.5/tk8.5/Resources/Scripts
~/Library/Frameworks/tk8.5
~/Library/Frameworks/tk8.5/Resources/Scripts /Library/Frameworks/tk8.5
/Library/Frameworks/tk8.5/Resources/Scripts
/System/Library/Frameworks/tk8.5
/System/Library/Frameworks/tk8.5/Resources/Scripts ./library