Autodesk just released Maya 2018 update 4 and new DevKit. You can find them at Maya Developer Center.
On Mac, lib files that required for building devkit plugins and standalone applications are located in Maya.app folder. This is incorrect and will be addressed in a future release.
To workaround this, you can either:
1) Create a folder named "lib" under devkitBase and copy lib files from Maya.app/Contents/MacOS and Maya.app/Contents/Resources to the newly created lib folder
2) Update linker paths (DEVKIT_LIB variable) in devkitBase/devkit/plug-ins/buildconfig to point to the folders inside Maya.app