bogus 'Please add USE_LANGUAGES+=c to the package Makefile' message

["Steven M. Bellovin" <smb%cs.columbia.edu@localhost>]

I'm working on a package for xml2rfc.  I ran my package and got the
message "Please add USE_LANGUAGES+=c to the package Makefile".  Fair
enough, except that it doesn't use C; it's written in tcl/tk.   What,
if anything, should I add to the Makefile?  I currently use

        DEPENDS+=       tcl>=8.0:../../lang/tcl