Use cmSystemTools to report some messages.
These should now be caught and displayed properly,
both in ccmake and cmake-gui

Avoid log display flickering during processing
- Don't clear the screen each time the long message form is rendered.
  It always renders the whole screen again so clearing it only causes
  flickering.
- Add scroll down capabilities to the long message form so that it can
  draw itself directly in the correct state. This removes the need to
  programatically scroll down just after that also caused flickering.

Fixes #19882
Fixes #13288