Bash script to download and build:

libraries for Android devices. Requires NDK only, no "gradlew" or java, C/C++ only.
How it works. Script gets SDL projects from

https://www.libsdl.org/release/
https://www.libsdl.org/projects/

and SDL2_gfx from

https://www.ferzkopp.net/wordpress/2016/01/02/sdl_gfx-sdl2_gfx/

Script downloads and unpacks archives to directory, sample command:

./build.sh --prefix=/home/user/build --ndkdir=/home/user/NDK --api=16 --arch=armeabi-v7a

Where "--prefix" sets build directory, "--ndkdir" sets NDK directory, "--api" sets minimal Android API level and "--arch" sets architecture of our librares. Available android API levels you can check in NDK "platforms" directory and architecture list:

armeabi-v7a
arm64-v8a
x86
x86_64

build.sh script is a wrapper to "ndk-build" script from NDK directory. If you plan improve script - NDK guides may be very helpfull.

 
https://developer.android.com/ndk/guides/android_mk

If you get an error when downloading, verify SDL archives versions first and then links in the script, version can be found in the begining and links at the end of script. To skip download phase you can get all archives manually and put in folder, also fix versions of archives in the build.sh if necessary. Here version of packages tested with build.sh:

android-ndk-r16b
android-ndk-r21b
SDL2-2.0.12
SDL2_image-2.0.5
SDL2_mixer-2.0.4
SDL2_net-2.0.1
SDL2_ttf-2.0.15
SDL2_gfx-1.0.4

Download ready libraries with minimal support android-16:
https://github.com/AlexanderAgd/SDL2-Android/releases
Build an example with SDL2:
https://github.com/AlexanderAgd/SDL2-Android-Example
Enjoy :)