http://bugs.winehq.org/show_bug.cgi?id=18120
--- Comment #30 from winterknight@nerdshack.com 2009-10-05 16:19:39 --- "It's hard to say if it is a Qt or a Wine problem"
I am assuming your diagnosis is correct. It sounds like it is.
This is a Wine problem. It is not doing whatever Windows is doing to pick a font. Is wine's goal still to be 100% bug for bug compatible? It might be a Qt problem too. That depends on whether Qt is using an undocumented feature/bug, or if wine is not doing something that Microsoft has appropriately documented.
"the fact is that it worked with some of the previous Wine builds at some time, using the same Qt version."
No it didn't. As soon as Qt 4.5.0 came out, lots of people started having these problems. I am using wine 1.0.1, the latest stable version. What wine version have you used that works with Qt 4.5.*
"Adding few lines inside Qt source code to provide an explicit substitution for the fonts, made all the text appear properly."
I bet providing your patch would be helpful. It couldn't hurt.