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
sudo -H pip3 install matplotlib
sudo -H pip3 install --global-option="build_ext" --global-option="-I/opt/X11/include/freetype2/" --global-option="-L/opt/X11/lib" matplotlib
freetype: no [The C/C++ header for freetype2 (ft2build.h)
could not be found. You may need to install the
* The following required packages can not be built:
matplotlib 1.5.3 or 2.0.0rc2, macOS Sierra, XQuartz 2.7.11, Xcode 8.2.1, Python 3.6.0
Happened to me too, using homebrew. Tried many things but what got it working in the end was:
ln -s /usr/local/include/freetype2/ft2build.h /usr/local/include/ft2build.h
Do you have pkgconfig installed?
Does it work if you set expert MPLLOCALFREETYPE=1?
I didn't have pkgconfig installed. I installed it, also tried to invoke pip3 with or without MPLLOCALFREETYPE=1, and still get the same error.