title: How to install PIL with pip on Mac OS?
body: <p>I am trying to install PIL (the Python Imaging Library) using the command:</p>
  <pre><code>sudo pip install pil
  </code></pre>
  <p>but I get the following message:</p>
  <pre><code>Downloading/unpacking PIL
    You are installing a potentially insecure and unverifiable file. Future versions of pip will default to disallowing insecure files.
    Downloading PIL-1.1.7.tar.gz (506kB): 506kB downloaded
    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
      clang -fno-strict-aliasing -fno-common -dynamic -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -mno-fused-madd -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch i386 -arch x86_64 -pipe -IlibImaging -I/System/Library/Frameworks/Python.framework/Versions/2.7/include -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c _imaging.c -o build/temp.macosx-10.8-intel-2.7/_imaging.o
      unable to execute clang: No such file or directory
      error: command 'clang' failed with exit status 1
      Complete output from command /usr/bin/python -c &quot;import setuptools;__file__='/private/tmp/pip_build_root/PIL/setup.py';exec(compile(open(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))&quot; install --record /tmp/pip-AYrxVD-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
  
  .
  .
  .
  .
  
  copying PIL/XVThumbImagePlugin.py -&gt; build/lib.macosx-10.8-intel-2.7
  
  running build_ext
  
  --- using frameworks at /System/Library/Frameworks
  
  building '_imaging' extension
  
  creating build/temp.macosx-10.8-intel-2.7
  
  creating build/temp.macosx-10.8-intel-2.7/libImaging
  
  clang -fno-strict-aliasing -fno-common -dynamic -g -Os -pipe -fno-common -fno-strict-aliasing -fwrapv -mno-fused-madd -DENABLE_DTRACE -DMACOSX -DNDEBUG -Wall -Wstrict-prototypes -Wshorten-64-to-32 -DNDEBUG -g -Os -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch i386 -arch x86_64 -pipe -IlibImaging -I/System/Library/Frameworks/Python.framework/Versions/2.7/include -I/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c _imaging.c -o build/temp.macosx-10.8-intel-2.7/_imaging.o
  
  unable to execute clang: No such file or directory
  
  error: command 'clang' failed with exit status 1
  
  ----------------------------------------
  Cleaning up…
  </code></pre>
  <p>Could you please help me to install <code>PIL</code>?</p>