Introduction
============

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.

Further documentation, including more detailed instructions on how to build and
install Tcllib/Tcllibc, is available at <https://core.tcl-lang.org/tcllib>
