use -trigraphs

Code:

---

warning: trigraph ??( ignored, use -trigraphs to enable

---

How to fix this error?
This happens when i start this app:
http://pic.mk/images/poddrska.jpg

I use QLabel *label = new Label(tr("Некој текст."));
The text is written in cirilyc.
I have enabled the unicode support for my language in the OS(Win 7).