On Mavericks, I downloaded the source code and and built and installed it with Distutils as I explained on Stackoverflow.
I try to reproduce it on Yosemite and I have the following error message:
Exception: pg_config tool is not available.
The command in 'setup.py' that generates the problem is supposed to "Retrieve information about installed version of PostgreSQL."
f = os.popen('pg_config --%s' % s
I used the graphic installer to install PostgreSQL on my computer.