The question here is not why the later developing versions can’t build, I don’t care. What I ask is why you don’t make v 2.0.6 available on Fdroid?
Upstream does not want us to distribute outdated versions: https://twitter.com/videolan/status/748448942141091840
Check this article to compile for Android
VLC build instructions look simple and straightforward until you start following them. Even minor differences in build environment can cause issues (like automake 1.15 vs 1.15.1).
Sometimes they forget to update their source code.
For example, VLC 2.5.2 requires libvlc to be built from commit 1c02164. But the version they distribute was built with libvlc from ef7c26f5a7 (you can get this from logcat, grep “core libvlc: revision”). BTW, this mismatch can be the reason why F-Droid’s VLC 2.5.2 crashes.
Official 2.5.3 uses libvlc built from cbfa98bd98, which has not been published at all.
Hopefully those examples explain why we cannot build VLC.