title: How to set the path for cairo in ubuntu-12.04?
body: <p>I need to install pycairo with python3.2+.But I have error when installing the pycairo in my system,</p>
  
  <pre><code>Downloading/unpacking git+http://anongit.freedesktop.org/git/pycairo (from -r requirements.txt (line 7))
    Cloning http://anongit.freedesktop.org/git/pycairo to /tmp/pip-ud145u-build
    Running setup.py egg_info for package from git+http://anongit.freedesktop.org/git/pycairo
      cairo &gt;= 1.10.2  Failed
      Package cairo was not found in the pkg-config search path.
      Perhaps you should add the directory containing `cairo.pc'
      to the PKG_CONFIG_PATH environment variable
      No package 'cairo' found
  
      Complete output from command python setup.py egg_info:
      cairo &gt;= 1.10.2  Failed
  
  Package cairo was not found in the pkg-config search path.
  
  Perhaps you should add the directory containing `cairo.pc'
  
  to the PKG_CONFIG_PATH environment variable
  
  No package 'cairo' found
  </code></pre>