Log Message:
Update to 2.0

for pkgsrc, this is the pure tcl version only (without the c runtime
in tcl) since the required prerequisite, critcl, is not in pkgsrc yet.
may try to add it soon...

=============
Tcllib 2.0 is the first major revision of Tcllib after a long series of
minor 1.x releases.

This revision

  1. __drops support__ for Tcl versions before 8.5.
       - All packages now require Tcl 8.5 as their minimum runtime.
       - This does not mean that the implementations are already changed to use
         Tcl 8.5 features.
       - Such changes will be done incrementally.
       - Users of Tcl 8.4 or even older still have Tcllib 1.21 available to them.

  2. __adds support__ for Tcl 9, for both Tcl and C implementations
     (where available).
       - It is the first revision to have such support.
       - Tcllib 1.21 and older will not work with Tcl 9.

  3. enhances the visibility of the __C accelerators__ available for various
     Tcllib packages through the adjunct __Tcllibc__ binary package.
     Tcllibc's version has become 2.0 also, to match Tcllib itself.
       - The Makefile's `install` target is extended to install both Tcllib and
         Tcllibc.
	 In other words, Tcllibc is now __built by default__, requiring a Critcl
	 installation.
	 Eben so, Tcllibc is __still optional__, and Tcllib can still be built
	 and installed without it.
       - To install only Tcllib use the new target `install-tcl`.
       - To install only Tcllibc use the new target `install-binaries`.
       - __Beware__ that Tcllibc, as a binary package, has to be compiled for
         either Tcl 8 or Tcl 9.
       - __Beware__, that the Tcllibc binary package requires Tcl 8.6 as its
       	 minimum runtime.
	 This is due to the Tcl 9 portability support, which requires 8.6 on the
       	 other side of the border.
	 This should not be true hardship.
	 Tcllib 1.21 is still available, and does not have this restriction.