There is a problem with the PlatformIO builder since the last update of @mvdbro
It's an issue with the parsing of `#ifdef ESP32`.
It is very well explained here: [platformio/platformio-core#801 (comment)](https://github.com/platformio/platformio-core/issues/801#issuecomment-252447178)
In short, the event handling functions for the wifi have been moved to a separate .h file, since those files will be parsed properly by the Library Dependency Finder (LDF) in PlatformIO 3.x