On Android, `long` has the width of the system, while `jlong` is always
64 bit. If we support `long` as a signature type equivalent to `jlong`,
then it becomes possible to write code that fails to compile, or in the
worst case crashes at runtime, on a 32bit system.
Instead, support quint64, which is always the same size as jlong.
Change-Id: I60432ec7411e697b5f6e1f153216ceee0af7e0f1
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>