NDK 26 dropped support for API levels < 21 [1] [2]. Do the same for our Android build, to ease the maintenance. Adapt configure.ac accordingly and drop the now obsolete code paths in Android Viewer Java code. This in also means that the same minSdkVersion will be used for all architectures now, while API level 21 was already used for the 64-bit variants (for which the minimum supported version was 21 anyway) and API level 19 was used for x86 and 32-bit ARM when building with NDK 24/25, API level 16 when building with NDK 23. According to [1] and [3], more than 99% of Android devices have at least Android version 5, i.e. support API level 21. [1] https://github.com/android/ndk/issues/1751 [2] https://developer.android.com/ndk/downloads/revision_history [3] https://apilevels.com/ Change-Id: I875e784dd4e62993f51059ae6a280d425cb49c0a Reviewed-on: https://gerrit.libreoffice.org/c/core/+/160334 Tested-by: Jenkins Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>