While building 0.6-rc on my Debian box, I get the following warnings:

dpkg-shlibdeps: Warning: debian/pokerth/usr/games/pokerth should not be linked against libpthread.so.0 (it does not use any of its symbols).
dpkg-shlibdeps: Warning: debian/pokerth/usr/games/pokerth should not be linked against libm.so.6 (it does not use any of its symbols).

dpkg-shlibdeps is usually right about such things, so please have a look on that

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.