Errors installing Matplotlib - clang

I recently had this issue as well, but I was using pip. If you have homebrew installed you can solve it by running the following commands:

brew install freetype
brew install libpng
brew link freetype
pip install git+https://github.com/matplotlib/matplotlib.git#egg=matplotlib-dev

theres actually an easier way! First see if X11 libraries are installed (ls /usr/X11/include)

If they aren't you may need to install X11

If they are then a simple fix is this:

cd /usr/X11/include
sudo ln -s freetype2/freetype

Basically for some reason its looking for the freetype library at /usr/X11 and its actually in the subfolder in freetype2. Odd - but it does then compile this way.