The field JniConstants::structStatFsClass doesn't exist anymore

Am I using the proper libnativehelper ?

Once again, I started with jni files from [Android 4.4_r07 libnativehelper](https://android.googlesource.com/platform/libnativehelper/+/android-4.4_r0.7).

FWIW, here's my current [libnativehelper](https://github.com/PerfectCarl/robovm/tree/link_windows_libcore64/vm/rt/android/libnativehelper)

I didn't research the real issue, I just jumped to the nearest field looking like the missing field: `JniConstants::structStatVfsClass`