and are also incompatible

We have a licensed installer which installs QT Creator 2.2.1 and QT 4.7.4. As far as I'm aware this is 32-bit only.

We have installed QT (using the above installer) on a 64-bit centOS 7 Linux PC.

Our application we are trying to build was previously built in 32-bit, we now require it to build in 64-bit (GCC compiler) and we have ported the source to be compatible with 64-bit.

What is the best way to allow QT to build/link this in 64-bit i.e. get compatible 64-bit shared libraries (.so files)?