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#19882Fixes#13288
88cfef0821