Itcl - the [incr Tcl] extension

Itcl commit 0d11f378d8 breaks iwidgets:

% package require iwidgets cannot inherit from "itk::Widget" (cannot inherit from "itk::Archetype" (can only handle options on class level))

After backing this changeset out of the Tcl 8.6.3 release tarball iwidgets works fine.

Good that you have a fix that you can apply locally while
this gets sorted out (even if it means keeping memleaks).

Any idea how it is that Itk or Iwidgets relies on the removed
hash table?  I could see no sign that the table was used
anywhere by anything.  Still cannot find it, so I must be looking
wrong.

Any chance that reverting just the change to itclInt.h will
also restore proper functioning?

Yes, just reverting itclInt.h is enough.

Fix committed.