Both Gradle and CMake have a strong late 1990's smell to them. While CMake is sort of a necessary evil in the C/C++ world, there's no excuse for dragging Gradle into the NDK, combining both build tools leads to a complexity explosion that rarely works and tends to break after either the NDK or SDK is updated, or somebody merely looks the wrong way at the build files.

Sure, building C/C++ code into an .so file kinda works but that's about it, try building the APK entirely with cmake, that's simply not supported, you'll have to integrate with Gradle. The result is a complexity clusterf*ck that's a nightmare to maintain.

The NDK team should take a long hard look at Emscripten to get some inspiration how native code development is integrated into a 'native-hostile' runtime platform.