Earlier quoted context omitted.
Only because Termux developers refuse to use Java APIs and don't accept Android isn't a POSIX clone.
Android certainly has an acceptable POSIX component when it's not artificially broken.
https://developer.android.com/ndk/guides/stable_apis
> Starting in Android 7.0, the system prevents apps from dynamically linking against non-NDK libraries, which may cause your app to crash. This change in behavior aims to create a consistent app experience across platform updates and different devices. Even though your code might not be linking against private libraries, it's possible that a third-party static library in your app could be doing so. Therefore, all developers should check to make sure that their apps do not crash on devices running Android 7.0. If your app uses native code, you should only be using public NDK APIs.
Taken from https://developer.android.com/about/versions/nougat/android-...