This might be caused by CONFIG += thread in pokerth_game.pro. However, according to the qt documentation this switch is needed in multi-threaded applications:
http://doc.trolltech.com/4.3/qmake-project-files.html#general-configuration

"thread - The project is a multi-threaded application."

As I see things, this issue only exists when dynamically linking to qt. I don't know any way to solve this. Anyway, because PokerTH indirectly depends on the named libs, it should be no problem.