tcl8: re-add tcl 8 to support building expect

tcl8: re-add tcl 8 to support building expect

I'd be happy to remove expect from core as it has been unmaintained for years,
but sadly gcc/binutils test suites are basically written in it (via dejagnu),
and ltp makes use of it as well.

I attempted porting expect to tcl 9, but it's a tcl extension and makes
extensive use of features that have been deprecated in tcl 8 and removed
in tcl 9, and even pokes into tcl internals.

At some point hopefully the GNU toolchain upstreams are going to notice;
for now we'll carry tcl (latest) and tcl8 recipes.

tcl and tcl8 packages can be co-installed, the latter is adjusted
to contain tclsh8.

tcl-dev and tcl8-dev packages can also be co-installed, a few files
in tcl8-dev are renamed to avoid clashes with tcl-dev (tcl.pc -> tcl8.pc,
and similar for tclConfig.sh and tclooConfig.sh).

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>