[FR] Provide static libraries as well

[bk138]

Is your feature request related to a problem? Please describe.
While linking an Android app's native code to .so files works reasonably well, there are a lot of unused symbols shipped in the resulting .apk, contained in the .so files.

Describe the solution you'd like
The AAR packages provide .a files as well, allowing linking to those and, as a result, allowing the compiling/linking machinery to strip symbols that aren't actually used by the program code, resulting in smaller .apk's.

Thus, an AAR would contain headers, static and dynamic libs, very much like Linux distros do it,

Describe alternatives you've considered
Right now we're building all dependencies as static libs from source.

Additional context
https://github.com/bk138/multivnc/blob/master/android/app/src/main/cpp/CMakeLists.txt is the project in question - would be nice to use static prefabs there :-).

[DanAlbert]

I've been meaning to find the time for this. Is there a particular package you want this for, or just in general?

[bk138]

OpenSSL would be nice for a start. Nonetheless, I reckon this would come in handy generally, too.

[alexcohn]

Yes, you can use static libraries with prefab. You can have static and shared libraries in the same prefab. The names of the static and shared library files can be the same (e.g. libssl.so and libssl.a), but the directory names under modules and library names in module.json must be different (e.g. libssl and libssl-static).

The only inconvenience is that you must include the headers twice, but @DanAlbert has been convincing me all along that duplication of some files in the AAR is not a problem at all.