OSX: error when installing python packages

Question

Currently, I am unable to install any Python packages due to a gcc-4.0 error. I'll copy two examples of the error I'm getting (one with pip, the other with a manual setup.py build/install approach):

sgarza62$ pip install PIL
Downloading/unpacking PIL
  Running setup.py egg_info for package PIL
    WARNING: '' not a valid package name; please use only.-separated package names in setup.py

Installing collected packages: PIL
  Running setup.py install for PIL
    WARNING: '' not a valid package name; please use only.-separated package names in setup.py
    --- using frameworks at /System/Library/Frameworks
    building '_imaging' extension
    gcc-4.0 -fno-strict-aliasing -fno-common -dynamic -arch ppc -arch i386 -g -O2 -DNDEBUG -g -O3 -DHAVE_LIBZ -I/System/Library/Frameworks/Tcl.framework/Headers -I/System/Library/Frameworks/Tk.framework/Headers -IlibImaging -I/Library/Frameworks/Python.framework/Versions/2.7/include -I/usr/include -I/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c _imaging.c -o build/temp.macosx-10.3-fat-2.7/_imaging.o
    unable to execute gcc-4.0: No such file or directory
    error: command 'gcc-4.0' failed with exit status 1
    Complete output from command /Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python -c "import setuptools;__file__='/var/folders/9q/bvqtzkbx1hg1934b36zgk0y40000gp/T/pip-build/PIL/setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /var/folders/9q/bvqtzkbx1hg1934b36zgk0y40000gp/T/pip-nV9YEx-record/install-record.txt --single-version-externally-managed:
    WARNING: '' not a valid package name; please use only.-separated package names in setup.py

running install

running build

running build_py

running build_ext

--- using frameworks at /System/Library/Frameworks

building '_imaging' extension

gcc-4.0 -fno-strict-aliasing -fno-common -dynamic -arch ppc -arch i386 -g -O2 -DNDEBUG -g -O3 -DHAVE_LIBZ -I/System/Library/Frameworks/Tcl.framework/Headers -I/System/Library/Frameworks/Tk.framework/Headers -IlibImaging -I/Library/Frameworks/Python.framework/Versions/2.7/include -I/usr/include -I/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c _imaging.c -o build/temp.macosx-10.3-fat-2.7/_imaging.o

unable to execute gcc-4.0: No such file or directory

error: command 'gcc-4.0' failed with exit status 1

---

sgarza62$ cd Imaging-1.1.7
sgarza62$ sudo python setup.py build
running build
running build_py
running build_ext
--- using frameworks at /System/Library/Frameworks
building '_imaging' extension
gcc-4.0 -fno-strict-aliasing -fno-common -dynamic -arch ppc -arch i386 -g -O2 -DNDEBUG -g -O3 -DHAVE_LIBZ -I/System/Library/Frameworks/Tcl.framework/Headers -I/System/Library/Frameworks/Tk.framework/Headers -IlibImaging -I/Library/Frameworks/Python.framework/Versions/2.7/include -I/usr/include -I/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c _imaging.c -o build/temp.macosx-10.3-fat-2.7/_imaging.o
unable to execute gcc-4.0: No such file or directory
error: command 'gcc-4.0' failed with exit status 1

---

Here is a bunch of information that I'll copy from the terminal, hopefully some of it is helpful in identifying the problem:

sgarza62$ gcc
i686-apple-darwin11-llvm-gcc-4.2: no input files

---

sgarza62$ python
Python 2.7.3 (v2.7.3:70274d53c1dd, Apr  9 2012, 20:32:06)
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>

---

sgarza62$ which python
/Library/Frameworks/Python.framework/Versions/2.7/bin/python

---

sgarza62$ echo $PATH
/Library/Frameworks/Python.framework/Versions/2.7/bin:/Library/Frameworks/Python.framework/Versions/2.7/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin

---

sgarza62$ /usr/bin/python -c 'import sys;print(sys.version)'
2.7.2 (default, Jun 16 2012, 12:38:40) 
[GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)]
sgarza62$ /usr/bin/python2.6 -c 'import sys; print(sys.version)'
2.6.7 (r267:88850, Jun 16 2012, 12:38:45) 
[GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)]
sgarza62$ /usr/bin/python2.5 -c 'import sys;print(sys.version)'
2.5.6 (r256:88840, Jun 16 2012, 12:38:24) 
[GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)]
sgarza62$ /usr/bin/python2.7 -c 'import sys;print(sys.version)'
2.7.2 (default, Jun 16 2012, 12:38:40) 
[GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)]

---

Here are some questions/answers on stack that address the same or similar problems (but that did not provide a full solution to my problem). Maybe these previous answers will be of use in figuring out this problem:

Reinstalling python on Mac OS 10.6 with a different gcc version

How to use/install gcc on Mac OS X 10.8 / Xcode 4.4

Python build using wrong version of GCC on OS X

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These are the things I have already done, which have been suggested be stack users for similar problems:

• Download Xcode

• Install Command Line Tools in the Xcode preferences

• sudo ln -s /usr/bin/gcc /usr/bin/gcc-4.2

---

I've done my best in the question to give as many facts, in a clear and orderly way, as possible. However, if you guys need any more information, please ask! I will be happy to edit the question with more details.

Also, I know this appears to be a very specific question, but from searching around, it looks like many others are confused about this problem.

If you don't mind, I would very much appreciate a spoon-fed solution (explicitly stating what I have to do in the Terminal to fix this). I am not very comfortable in the Terminal yet, and get a bit confused with generalized answers.

Thank you all for your time, I appreciate it!

Answer 1

The problem here is that you are trying to use the 32-bit-only python.org 2.7.3 on an OS X system with Xcode 4. The 32-bit-only installer was designed to be compatible across a number of OS X releases going back to 10.3.9. Unfortunately, with the removal of PPC support in Xcode 4 and various other changes made there, installing third-party Python packages that have C extension modules does not work out-of-the-box anymore on 10.7 and later systems with Xcode 4. It is possible to work around them, though. In the case of PIL, changing a couple of Python Distutils defaults through environment variables should do the trick:

# override the default gcc-4.0 compiler and use clang instead
$ export CC=clang
# override the universal architectures to only use Intel-32
$ export ARCHFLAGS='-arch i386'
$ pip install PIL

The python.org website provides two OS X installer variants for current Python releases. The Python provided by the other installer, the 64-bit/32-bit version, is configured for a smaller, newer range of systems; it does not support PPC and wouldn't have this problem with Xcode 4.

BTW, the next release of Python 2.7 (2.7.4) provides better support for Xcode 4 with both installers and should not have this problem.