tar -xzf tcl8.6.0-src.tar.gz 
cd tcl8.6.0/unix
./configure --prefix=/tools
make
TZ=UTC make test
make install
chmod -v u+w /tools/lib/libtcl8.6.so
make install-private-headers
ln -sv tclsh8.6 /tools/bin/tclsh
cd ../../
rm -fr tcl8.6.0