compile of graphviz-2.40.1 failed

during a build of graphviz-2.40.1
==>  graphviz-2.40.1 option TCL is required for option TK.
*** Error code 1

make[7]: stopped in /usr/ports/graphics/graphviz
*** Error code 1

will install TCL and then recompile.
Like the error message says the option TK requires that you also enable the option TCL, so run make config and enable (or disable) both the TCL and TK options.

I don't understand why the port doesn't do this automatically though, so I've filed PR 216791.