[PyQt] qreal check needs to be fixed for Qt 5.2

[Dmitry Shachnev]

Hi,

Since Qt 5.2, qreal is double on *all* platforms by default, so the
check in PyQt5's configure.py does not work and causes build failure
on arm:

https://launchpadlibrarian.net/164027747/buildlog_ubuntu-trusty-armhf.pyqt5_1%3A5.2%2Bdfsg-0~10%2B201401291329~ubuntu14.04.1_FAILEDTOBUILD.txt.gz

Reverting to the sizeof-based check that was in PyQt 5.0 makes it work
again with both all and new Qt. Why was it changed?

--
Dmitry Shachnev