Documentation missing list of NDK version used per Qt version

It would be helpful to have a table of Qt versions with NDK versions in the Qt for Android documentation, and to document a strong recommendation for users to use the same NDK version that Qt was built with.

Each Qt release for Android is built using a specific NDK release, but this doesn’t seem to be properly documented. However, Google says:

All libraries should be generated with the same NDK version.

This rule is a bit more flexible than most, but in general NDK code is only guaranteed to be compatible with code generated with the same version of the NDK (minor revision mismatches generally okay).

Thus it’s important for users of Qt Android to know which NDK version was used to built Qt, so that they can use the same NDK version. (Anecdotally, I recently tried using NDK r21 with Qt 5.14.1 and got some seemingly random crashes in Qt atomic operations.)

The Qt for Android documentation currently says:

For Qt 5.12 or later, use the latest available version of NDK with android-clang toolchain.

Based on the above this is misleading and insufficient information, as the latest NDK version might in fact not work correctly with a given Qt release. The Android page in the Qt wiki has some more specific and helpful information, but which contradicts the documentation page (because r18b and r20 are not the "latest available version of the NDK"):

• Important: As of Qt 5.12, Android NDK r18b is required, and GCC toolchains are no longer supported in the android NDK.
• Important: As of Qt 5.14, Android NDK r20 is required, and GCC toolchains are no longer supported in Qt as well.

The above information has also been requested in the Qt forums.