PyQt5 install using the python3-sip standard package
I faced the same problem yesterday. I solved it on Ubunutu 13.10 by removing the python3-sip package to which the PyQt5 installation seemed to refer to.
sudo apt-get remove python3-sip
and cleanup :
sudo apt-get autoremove
then install again sip 4.15.5 & PyQt5 in fresh environments (make clean) or restore the source directories.
Note : Some PyQt5 libraries (graphic based) lake for me after the installation. I had to install the libgl1-mesa-dev package before re-installing.
Hope that could help you.