When running configure and selecting the Open Source Edition, only the Lesser GNU General Public License version 2.1 (aka LGPL v2) is offered. According to Qt Project's download page (http://qt-project.org/downloads), and as stated in source code files, Qt is available also under GPL v3.
The problem is that configure offers the GPL v3 option only if there is a file LICENSE.GPL3 which it may display upon user request. However, this file does not exist. The GPL v3 license text is supplied in LICENSE.GPL.
BTW, the download page's "Learn more about licenses here" link points to another page (http://qt-project.org/products/licensing) which fails to mention the GNU General Public License version 3 option.