graphics/py3-cairo cannot find Python.h, but Python.h is present

[tech-lists]

also, it's uninstallable from the pkg repo, even though freshports 
suggests it should be:

# pkg install py34-cairo
Updating FreeBSD repository catalogue...
FreeBSD repository is up-to-date.
All repositories are up-to-date.
pkg: No packages available to install matching 'py34-cairo' have been 
found in the repositories

-- 
J.