Without HarfBuzz it is not possible to use Unicode Private Use Area characters

The width reported for a character used from Unicode Private Use Area seems to be always reported as '0' (regardless if the font contains the character or not) if HarfBuzz is not available.

Expected behavior: If HarfBuzz is necessary to draw such characters, at least the character should be represented by a placeholder like other unavailable characters and this should also be logged. Now, if you happen to do

QLabel label("\ue000");
label.show();

This widget will never be shown.

In Qt Quick, Text will occupy space, but there will be nothing drawn inside (not even a placeholder).