Setting a negative line width does not make much sense, but in
earlier Qt versions, this work the same as if the line width was 0
(just give you the minimal layout given wrapping constraints).
But since 991c056438, we check if
current width > line width at an earlier point, and because 0 > -1,
we would exit immediately before adding any characters to the text
line.
To restore the behavior in earlier versions, we set the minimum
possible line width to 0.
Pick-to: 6.5
Fixes: QTBUG-109474
Change-Id: Iceadd5135681f61b30de8221853834983941c5a4
Reviewed-by: Lars Knoll <lars@knoll.priv.no>
Reviewed-by: hjk <hjk@qt.io>