clang error: unknown argument: '-mno-fused-madd' (python package installation failure)

Question

I get the following error when attempting to install psycopg2 via pip on Mavericks 10.9:

clang: error: unknown argument: \'-mno-fused-madd\' [-W         


        

Answer 1

You're probably on Python 2.7.5

$ python

Python 2.7.5 (default, Aug 25 2013, 00:04:04)  [GCC 4.2.1 Compatible
Apple LLVM 5.0 (clang-500.0.68)] on darwin

Easiest solution go to www.python.org and install Python 2.7.6 which is compatible with the LLVM 5.1.

Then toast your old virtual environment, rmvirtualenv {virtual_env_name}.

Then make a new virtual env..

mkvirtualenv --no-site-packages -p/Library/Frameworks/Python.framework/Versions/2.7/bin/python {virtual_env_name}

pip should work fine after this.