Make this work with what TCL/TK are installed in case, Insight is
requested. This required an explicit inclusion of bsd.tcl.mk -- because
options-parsing occurs in bsd.ports.pre.mk, and it is too late to
set USE_TK after that. Don't know a better way around :(
Also update the iTcl version to 3.4...
Freshen up to work with Tcl-8.5, which is a default, and is a bit
pickier about package version-numbers.
Notified by: Bruce Cran