Bug report

Bug summary

The macOS Sierra is updated to the latest version. We install matplotlib with Python 3.6.0. We have the latest XQuartz installed as well. matplotlib complains he cannot find header files for freetype2 although it's installed by XQuartz.

Code for reproduction

Either

sudo -H pip3 install matplotlib

or

sudo -H pip3 install --global-option="build_ext" --global-option="-I/opt/X11/include/freetype2/" --global-option="-L/opt/X11/lib" matplotlib

Actual outcome

freetype: no  [The C/C++ header for freetype2 (ft2build.h)
                            could not be found.  You may need to install the
                            development package.]
...
                            * The following required packages can not be built:
                            * freetype

Matplotlib version

matplotlib 1.5.3 or 2.0.0rc2, macOS Sierra, XQuartz 2.7.11, Xcode 8.2.1, Python 3.6.0