Where is "one line fix"? Changing linux-g++-maemo? In any case it requires running "configure" and it's parameters issue is still here.
mkdir qt chdir qt apt-get source libqt4-dev chdir qt4-x11-4.7.0~git20100909 sed -i 's/linux-host-g++/linux-g++-maemo5/' configure dpkg-buildpackage -b -d -nc -rfakeroot