Missing gcc-4.0 error on pip install twisted in virtual env - twisted

Question

I'm trying to use Scrapy inside a virtualenv, which requires installation of twisted as well. I did pip install Scrapy with no problems, but when I try pip install twisted, I'm getting the following error multiple times in the output:
unable to execute gcc-4.0: No such file or directory
error: command 'gcc-4.0' failed with exit status 1
I previously had a similar problem when trying to install python packages on my actual system, which is why I started using virtualenv in the first place. Is this an issue of the python version installed on my environment? This is what I currently have:
Django - 1.5 - active
Python - 2.7.3 - active development (/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload)
Scrapy - 0.16.4 - active
pip - 1.2.1 - active
setuptools - 0.6c11 - active
wsgiref - 0.1.2 - active development (/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7)
yolk - 0.4.3 - active
To check which version of gcc I have I typed gcc at the command line and got
i686-apple-darwin11-llvm-gcc-4.2: no input files
I tried export CC=gcc-4.2 before running pip install twisted, and I got:
llvm-gcc-4.2: error trying to exec '/usr/bin/../llvm-gcc-4.2/bin/powerpc-apple-darwin11-llvm-gcc-4.2': execvp: No such file or directory
lipo: can't figure out the architecture type of: /var/folders/s8/d0f65gc93nbchdk52g2cg5f80000gn/T//ccWQa7cJ.out
error: command 'gcc-4.2' failed with exit status 255
It sort of looks to me like it's looking for powerpc-apple-darwin11-llvm-gcc-4.2, and what I have above is i686-apple-darwin11-llvm-gcc-4.2--are these different and therefore causing the problem?
To give more background info, I installed Python 2.7 from a Python.org installer a long time ago before upgrading from Snow Leopard straight to Mountain Lion. If I simply type in python at the command line I get
Python 2.7.3 (v2.7.3:70274d53c1dd, Apr 9 2012, 20:32:06)
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin
So I'm guessing that means I'm using Apple's Python? And it's built with gcc-4.0.1? So if that's the case, shouldn't I not need to do the export CC=gcc-4.2? Or do I need to do that AND switch to the Python.org version of Python? (And if the latter, how do I do that?)
Update: I tried this solution for switching Python versions but it didn't work.
Update: I managed to switch Python versions (outside of my virtualenv) using the sudo port select --set python python27 command, but this didn't solve the problem even though I'm now showing:
Python 2.7.3 (default, Nov 17 2012, 19:54:34)
[GCC 4.2.1 Compatible Apple Clang 4.1 ((tags/Apple/clang-421.11.66))] on darwin
when I type python at the commmand line.
Update: I also found this solution to a question that seemed to have almost the exact same issues as I'm having, but I'm already upgraded to XCode 4.6 and definitely have the Command Line Tools installed as described in the aforementioned solution (Preferences>Downloads tab>Install Command Line Tools). I do also have XCode 3.2.6 installed, however--any chance that's causing my problems?

Answer 1

Have you tried CC="$(type -p clang)" pip install twisted? You don't necessarily need to use gcc to compile Twisted's extensions; selecting clang instead might clear up whatever weird problem seems to be infesting your gcc installation.
If that doesn't work, I would suggest un-installing any Python.org versions of Python and then possibly re-installing both the OS and Xcode, since it looks like something might have corrupted your system Python install. I have no idea how references to powerpc stuff have persisted into Mountain Lion, since Lion removed support for ppc.