lang/tclx: import tclx-8.6.3

Packaged for wip by adr.

Extended Tcl (TclX), is an extension to Tcl, the Tool Command
Language invented by Dr. John Ousterhout.  Tcl is a powerful, yet
simple embeddable programming language.  Extended Tcl is oriented
towards system programming tasks and large application development.
TclX provides additional interfaces to the operating system, and
adds many new programming constructs, text manipulation tools, and
debugging tools.

(wiz)