Include of Non-Modular framework error when allow non-modular imports set to YES

**Background** I'm building an API framework in Swift. I want it to include a `Reachability` class that can be used internally and externally.

**Status** I've copied the source of the `Reachability` class provided by Tony Million, added the import statement to my header. The `.h` file is set to public in the `Headers` section of `Build Phases`. I've set `Allow Non-modular Includes in Framework Modules` to `YES` in both my project and target. Whenever I go to build the project, I get the error:

Include of non-modular header inside framework module 'MyFramework.Reachability'

on the line that imports `ifaddrs.h`.

How can I get my project to build? Is there another framework I need to link against that isn't `SystemConfiguration`?