If someone is using 32-bit Linux GCC, you might run into an issue of SSE not being enabled by default. Before, it was necessary to put it into the Makefile manually after running qmake. With an upcoming update, it will be enough to set the environment variable QMAKESPEC=linux-g++-32 in order for qmake to do this automatically.

If you are on other platforms than 32-bit Linux GCC, you are not affected by this.