如何在ubuntu-12.04中设置cairo的路径？

我需要用
python3.2安装pycairo.但是在我的系统中安装pycairo时出错了,

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 >= 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 >= 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

首先安装libcairo2-dev：

sudo apt-get install libcairo2-dev