Installation issue on python3

There is a minor installation issue with dependencies.

Although pycairo for python3 is already installed, configure complains that it is not there. Once I install pycairo or python 2.7 it works fine.

I think the problem is that configure looks for "pycairo.h" in /usr/include/pycairo/, but for python3 the file is named "py3cairo.h"