Merge branch 'cc/no-gitk-build-dependency'

Remove leftover bits from an earlier change to move gitk in its own subdirectory. Reimplementing the dependency tracking rules needs to be done in gitk history separately. * cc/no-gitk-build-dependency: Makefile: replace "echo 1>..." with "echo >..." Makefile: detect when PYTHON_PATH changes Makefile: remove tracking of TCLTK_PATH